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A square inch is a unit of area, equal to the area of a square with sides of one inch. The square inch is a common unit of measurement in the United States and the United Kingdom. Pounds per square inch (psi), a unit of pressure, are derived from this unit of area.

The square mile is an imperial and US unit of measure for area. One square mile is equal to the area of a square with each side measuring a length of one mile.

unit of area

The square metre or square meter is the unit of area in the International System of Units (SI) with symbol m2. It is the area of a square with sides one metre in length.

The square metre or square meter is the unit of area in the International System of Units (SI) with symbol m2. It is the area of a square with sides one metre in length.

unit of area

The hectare is a non-SI metric unit of area equal to a square with 100-metre sides (1??hm2), that is, 10,000 square metres, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is about 0.405 hectares and thus one hectare is about 2.47 acres.

A survey township, sometimes called a Congressional township or just township, as used by the United States Public Land Survey System and by Canada's Dominion Land Survey is a nominally-square area of land that is nominally six survey miles on a side. Each 36-square-mile township is divided into 36 sections of one square mile each. The sections can be further subdivided for sale.

The square kilometre is a multiple of the square metre, the SI unit of area or surface area. In the SI unit of area (m2), 1 km2 is equal to 1M(m2).

The acre is a unit of land area used in the British imperial and the United States customary systems. It is traditionally defined as the area of one chain by one furlong, which is exactly equal to 10 square chains, 1???640 of a square mile, 4,840 square yards, or 43,560 square feet, and approximately 4,047??m2, or about 40% of a hectare. The acre is sometimes abbreviated ac, but is usually spelled out as the word "acre".

The square foot is an imperial unit and U.S. customary unit of area, used mainly in the United States, Canada, the United Kingdom, Bangladesh, India, Nepal, Pakistan, Ghana, Liberia, Malaysia, Myanmar, Singapore and Hong Kong. It is defined as the area of a square with sides of 1 foot.

Zirconium is a chemical element; it has symbol Zr and atomic number 40. First identified in 1789, isolated in impure form in 1824, and manufactured at scale by 1925, pure zirconium is a lustrous transition metal with a greyish-white color that closely resembles hafnium and, to a lesser extent, titanium. It is solid at room temperature, ductile, malleable and corrosion-resistant. The name zirconium is derived from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian zargun. Besides zircon, zirconium occurs in over 140 other minerals, including baddeleyite and eudialyte; most zirconium is produced as a byproduct of minerals mined for titanium and tin.

Niobium is a chemical element; it has symbol Nb and atomic number 41. It is a light grey, crystalline transition metal. Pure niobium has a Mohs hardness rating similar to pure titanium, and it has similar ductility to iron. Niobium oxidizes in Earth's atmosphere very slowly, hence its application in jewelry as a hypoallergenic alternative to nickel. Niobium is found in the minerals pyrochlore and columbite, as well as other minerals. Its name comes from Greek mythology: Niobe, daughter of Tantalus, the namesake of tantalum. The name reflects the great similarity between the two elements in their physical and chemical properties, which makes them difficult to distinguish.

Molybdenum is a chemical element; it has symbol Mo and atomic number 42. The name is derived from Ancient Greek ???????????????? m??lybdos, meaning lead, since its ores were sometimes confused with those of lead. Molybdenum minerals have been known throughout history, but the element was discovered in 1778 by Carl Wilhelm Scheele. The metal was first isolated in 1781 by Peter Jacob Hjelm.

Technetium is a chemical element; it has symbol Tc and atomic number 43. It is the lightest element whose isotopes are all radioactive. Technetium is one of only two radioactive elements both preceded and succeeded in the periodic table by elements with stable forms, the other being promethium. All available technetium is produced as a synthetic element. Naturally occurring technetium is a spontaneous fission product in uranium ore and thorium ore, or the product of neutron capture in molybdenum ores. This silvery gray, crystalline transition metal lies between manganese and rhenium in group??7 of the periodic table, and its chemical properties are intermediate between those of both adjacent elements. The most common naturally occurring isotope is 99Tc, in traces only.

Ruthenium is a chemical element; it has symbol Ru and atomic number??44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is unreactive to most chemicals. Karl Ernst Claus, a Russian scientist of Baltic-German ancestry, discovered the element in 1844 at Kazan State University and named it in honor of Russia, using the Latin name Ruthenia. Ruthenium is usually found as a minor component of platinum ores; the annual production has risen from about 19??tonnes in 2009 to 35.5??tonnes in 2017. Most ruthenium produced is used in wear-resistant electrical contacts and thick-film resistors. A minor application for ruthenium is in platinum alloys and as a chemical catalyst. A new application of ruthenium is as the capping layer for extreme ultraviolet photomasks in semiconductor lithography. Ruthenium is generally found in ores with the other platinum group metals in the Ural Mountains and in North and South America. Small but c

Rhodium is a chemical element; it has symbol Rh and atomic number 45. It is a very rare, dark silvery-white, hard, corrosion-resistant transition metal. It is a noble metal and a member of the platinum group. It has only one naturally occurring isotope, which is 103Rh. Naturally occurring rhodium is usually found as a free metal or as an alloy with similar metals and rarely as a chemical compound in minerals such as bowieite and rhodplumsite. It is one of the rarest and most valuable precious metals. Rhodium is a group 9 element. It is used for the enhancement of jewelry.

Palladium is a chemical element; it has the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1802 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired by her when she slew Pallas. Palladium, platinum, rhodium, ruthenium, iridium and osmium form together a group of elements referred to as the platinum group metals. They have similar chemical properties, but palladium has the lowest melting point and is the least dense of them.

Silver is a chemical element; it has symbol Ag and atomic number 47. A soft, whitish-gray, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. Silver is found in the Earth's crust in the pure, free elemental form, as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc refining.

Cadmium is a chemical element; it has symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of its compounds, and like mercury, it has a lower melting point than the transition metals in groups 3 through 11. Cadmium and its congeners in group 12 are often not considered transition metals, in that they do not have partly filled d or f electron shells in the elemental or common oxidation states. The average concentration of cadmium in Earth's crust is between 0.1 and 0.5 parts per million (ppm). It was discovered in 1817 simultaneously by Stromeyer and Hermann, both in Germany, as an impurity in zinc carbonate.

Indium is a chemical element; its symbol is In and its atomic number is 49. It is a silvery-white post-transition metal and one of the softest elements. Chemically, indium is similar to gallium and thallium, and its properties are largely intermediate between the two. It was discovered in 1863 by Ferdinand Reich and Hieronymous Theodor Richter by spectroscopic methods and named for the indigo blue line in its spectrum.

Tin is a chemical element; it has the symbol Sn and atomic number 50. A metallic-gray metal, tin is soft enough to be cut with little force, and a bar of tin can be bent by hand with little effort. When bent, a bar of tin makes a sound, the so-called "tin cry", as a result of twinning in tin crystals.

Uranium is a chemical element; it has symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium radioactively decays, usually by emitting an alpha particle. The half-life of this decay varies between 159,200 and 4.5??billion years for different isotopes, making them useful for dating the age of the Earth. The most common isotopes in natural uranium are uranium-238 and uranium-235. Uranium has the highest atomic weight of the primordially occurring elements. Its density is about 70% higher than that of lead and slightly lower than that of gold or tungsten. It occurs naturally in low concentrations of a few parts per million in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite.

Antimony is a chemical element with the symbol Sb and atomic number 51. A lustrous grey metal or metalloid, it occurs in nature mainly in the form of the sulfide mineral stibnite. Antimony compounds have been known since ancient times and were powdered for use as medicine and cosmetics, often known by the Arabic name kohl.

Tellurium is a chemical element; it has the symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally found in its native form as elemental crystals. Tellurium is far more common in the universe as a whole than on Earth. Its extreme rarity in the Earth's crust, comparable to that of platinum, is due partly to its formation of a volatile hydride that caused tellurium to be lost to space as a gas during the hot nebular formation of Earth.

Plutonium is a chemical element; it has symbol Pu and atomic number 94. It is a silvery-gray actinide metal that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation states. It reacts with carbon, halogens, nitrogen, silicon and hydrogen. When exposed to moist air, it forms oxides and hydrides that can expand the sample up to 70% in volume, which in turn flake off as a powder that is pyrophoric. It is radioactive and can accumulate in bones, which makes the handling of plutonium dangerous.

Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at 114????C (237????F), and boils to a violet gas at 184????C (363????F). The element was discovered by the French chemist Bernard Courtois in 1811 and was named two years later by Joseph Louis Gay-Lussac, after the Ancient Greek ??????????, meaning 'violet'.

Neptunium is a chemical element; it has symbol Np and atomic number 93. A radioactive actinide metal, neptunium is the first transuranic element. It is named after Neptune, the planet beyond Uranus in the Solar System, which uranium is named after. A neptunium atom has 93 protons and 93 electrons, of which seven are valence electrons. Neptunium metal is silvery and tarnishes when exposed to air. The element occurs in three allotropic forms and it normally exhibits five oxidation states, ranging from +3 to +7. Like all actinides, it is radioactive, poisonous, pyrophoric, and capable of accumulating in bones, which makes the handling of neptunium dangerous.

Xenon is a chemical element; it has symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, the first noble gas compound to be synthesized.

Caesium is a chemical element; it has symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of 28.5????C, which makes it one of only five elemental metals that are liquid at or near room temperature. Caesium has physical and chemical properties similar to those of rubidium and potassium. It is pyrophoric and reacts with water even at ???116????C (???177????F). It is the least electronegative stable element, with a value of 0.79 on the Pauling scale. It has only one stable isotope, caesium-133. Caesium is mined mostly from pollucite. Caesium-137, a fission product, is extracted from waste produced by nuclear reactors. It has the largest atomic radius of all elements whose radii have been measured or calculated, at about 260 picometres.

Protactinium is a chemical element; it has symbol Pa and atomic number 91. It is a dense, radioactive, silvery-gray actinide metal which readily reacts with oxygen, water vapor, and inorganic acids. It forms various chemical compounds, in which protactinium is usually present in the oxidation state +5, but it can also assume +4 and even +3 or +2 states. Concentrations of protactinium in the Earth's crust are typically a few parts per trillion, but may reach up to a few parts per million in some uraninite ore deposits. Because of its scarcity, high radioactivity, and high toxicity, there are currently no uses for protactinium outside scientific research, and for this purpose, protactinium is mostly extracted from spent nuclear fuel.

Barium is a chemical element; it has symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element.

Thorium is a chemical element; it has symbol Th and atomic number 90. Thorium is a weakly radioactive light silver metal which tarnishes olive grey when it is exposed to air, forming thorium dioxide; it is moderately soft, malleable, and has a high melting point. Thorium is an electropositive actinide whose chemistry is dominated by the +4 oxidation state; it is quite reactive and can ignite in air when finely divided.

Hafnium is a chemical element; it has symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in many zirconium minerals. Its existence was predicted by Dmitri Mendeleev in 1869, though it was not identified until 1922, by Dirk Coster and George de Hevesy. Hafnium is named after Hafnia, the Latin name for Copenhagen, where it was discovered. The element is obtained only by separation from zirconium, with most of the world's hafnium production coming from processes that also produce zirconium. These processes make use of heavy mineral sands ore deposits, which include the minerals zircon, rutile, and ilmenite, among others.

Actinium is a chemical element; it has symbol Ac and atomic number??89. It was discovered by Friedrich Oskar Giesel in 1902, who gave it the name emanium; the element got its name by being wrongly identified with a substance Andr??-Louis Debierne found in 1899 and called actinium. The actinide series, a set of 15 elements between actinium and lawrencium in the periodic table, is named after actinium. Together with polonium, radium, and radon, actinium was one of the first non-primordial radioactive elements to be discovered.

Tantalum is a chemical element; it has symbol Ta and atomic number 73. It is named after Tantalus, a figure in Greek mythology. Tantalum is a very hard, ductile, lustrous, blue-gray transition metal that is highly corrosion-resistant. It is part of the refractory metals group, which are widely used as components of strong high-melting-point alloys. It is a group 5 element, along with vanadium and niobium, and it always occurs in geologic sources together with the chemically similar niobium, mainly in the mineral groups tantalite, columbite, and coltan.

Radium is a chemical element; it has symbol Ra and atomic number 88. It is the sixth element in group??2 of the periodic table, also known as the alkaline earth metals. Pure radium is silvery-white, but it readily reacts with nitrogen (rather than oxygen) upon exposure to air, forming a black surface layer of radium nitride (Ra3N2). All isotopes of radium are radioactive, the most stable isotope being radium-226 with a half-life of 1,600??years. When radium decays, it emits ionizing radiation as a by-product, which can excite fluorescent chemicals and cause radioluminescence. For this property, it was widely used in self-luminous paints following its discovery. Of the radioactive elements that occur in quantity, radium is considered particularly toxic, and it is carcinogenic due to the radioactivity of both it and its immediate decay product radon as well as its tendency to accumulate in the bones.

Radon is a chemical element; it has symbol Rn and atomic number 86. It is a radioactive noble gas and is colorless and odorless. Of the three naturally occurring radon isotopes, only 222Rn has a sufficiently long half-life for it to be released from the soil and rock where it is generated. Radon isotopes are the immediate decay products of radium isotopes.

Rutherfordium is a synthetic chemical element; it has symbol Rf and atomic number 104. It is named after physicist Ernest Rutherford. As a synthetic element, it is not found in nature and can only be made in a particle accelerator. It is radioactive; the most stable known isotope, 267Rf, has a half-life of about 48 minutes.

Dubnium is a synthetic chemical element; it has symbol Db and atomic number 105. It is highly radioactive: the most stable known isotope, dubnium-268, has a half-life of about 16 hours. This greatly limits extended research on the element.

Seaborgium is a synthetic chemical element; it has symbol Sg and atomic number 106. It is named after the American nuclear chemist Glenn T. Seaborg. As a synthetic element, it can be created in a laboratory but is not found in nature. It is also radioactive; the most stable known isotopes have half-lives on the order of several minutes.

Bohrium is a synthetic chemical element; it has symbol Bh and atomic number 107. It is named after Danish physicist Niels Bohr. As a synthetic element, it can be created in particle accelerators but is not found in nature. All known isotopes of bohrium are highly radioactive; the most stable known isotope is 270Bh with a half-life of approximately 2.4 minutes, though the unconfirmed 278Bh may have a longer half-life of about 11.5 minutes.

Hassium is a synthetic chemical element; it has symbol Hs and atomic number 108. It is highly radioactive: its most stable known isotopes have half-lives of about ten seconds. One of its isotopes, 270Hs, has magic numbers of protons and neutrons for deformed nuclei, giving it greater stability against spontaneous fission. Hassium is a superheavy element; it has been produced in a laboratory in very small quantities by fusing heavy nuclei with lighter ones. Natural occurrences of hassium have been hypothesized but never found.

Meitnerium is a synthetic chemical element; it has symbol Mt and atomic number 109. It is an extremely radioactive synthetic element. The most stable known isotope, meitnerium-278, has a half-life of 4.5 seconds, although the unconfirmed meitnerium-282 may have a longer half-life of 67 seconds. The element was first synthesized in August 1982 by the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany, and it was named after the Austrian-Swedish nuclear physicist Lise Meitner in 1997.

Darmstadtium is a synthetic chemical element; it has symbol Ds and atomic number 110. It is extremely radioactive: the most stable known isotope, darmstadtium-281, has a half-life of approximately 14 seconds. Darmstadtium was first created in November 1994 by the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, after which it was named.

Roentgenium is a synthetic chemical element; it has symbol Rg and atomic number 111. It is extremely radioactive and can only be created in a laboratory. The most stable known isotope, roentgenium-282, has a half-life of 130 seconds, although the unconfirmed roentgenium-286 may have a longer half-life of about 10.7??minutes. Roentgenium was first created in December 1994 by the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany. It is named after the physicist Wilhelm R??ntgen, who discovered X-rays. Only a few roentgenium atoms have ever been synthesized, and they have no practical application.

Copernicium is a synthetic chemical element; it has symbol Cn and atomic number 112. Its known isotopes are extremely radioactive, and have only been created in a laboratory. The most stable known isotope, copernicium-285, has a half-life of approximately 30 seconds. Copernicium was first created in February 1996 by the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany. It was named after the astronomer Nicolaus Copernicus on his 537th anniversary.

Nihonium is a synthetic chemical element; it has symbol Nh and atomic number 113. It is extremely radioactive: its most stable known isotope, nihonium-286, has a half-life of about 10 seconds. In the periodic table, nihonium is a transactinide element in the p-block. It is a member of period 7 and group 13.

Flerovium is a synthetic chemical element; it has symbol Fl and atomic number 114. It is an extremely radioactive, superheavy element, named after the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research in Dubna, Russia, where the element was discovered in 1999. The lab's name, in turn, honours Russian physicist Georgy Flyorov. IUPAC adopted the name on 30 May 2012. The name and symbol had previously been proposed for element 102 (nobelium) but were not accepted by IUPAC at that time.

Moscovium is a synthetic chemical element; it has symbol Mc and atomic number 115. It was first synthesized in 2003 by a joint team of Russian and American scientists at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. In December 2015, it was recognized as one of four new elements by the Joint Working Party of international scientific bodies IUPAC and IUPAP. On 28 November 2016, it was officially named after the Moscow Oblast, in which the JINR is situated.

Livermorium is a synthetic chemical element; it has symbol Lv and atomic number 116. It is an extremely radioactive element that has only been created in a laboratory setting and has not been observed in nature; about 35 livermorium atoms had been made as of 2020. The element is named after the Lawrence Livermore National Laboratory in the United States, which collaborated with the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, to discover livermorium during experiments conducted between 2000 and 2006. The name of the laboratory refers to the city of Livermore, California, where it is located, which in turn was named after the rancher and landowner Robert Livermore. The name was adopted by IUPAC on May 30, 2012. Six isotopes of livermorium are known, with mass numbers of 288???293 inclusive; the longest-lived among them is livermorium-293 with a half-life of about 80??milliseconds. A seventh possible isotope with mass number 294 has been reported but not yet confirmed.

Tennessine is a synthetic element; it has symbol Ts and atomic number 117. It has the second-highest atomic number, the joint-highest atomic mass of all known elements, and is the penultimate element of the 7th period of the periodic table. It is named after the U.S. state of Tennessee, where key research institutions involved in its discovery are located.

Oganesson is a synthetic chemical element; it has symbol Og and atomic number 118. It was first synthesized in 2002 at the Joint Institute for Nuclear Research (JINR) in Dubna, near Moscow, Russia, by a joint team of Russian and American scientists. In December 2015, it was recognized as one of four new elements by the Joint Working Party of the international scientific bodies IUPAC and IUPAP. It was formally named on 28 November 2016. The name honors the nuclear physicist Yuri Oganessian, who played a leading role in the discovery of the heaviest elements in the periodic table.

Cerium is a chemical element; it has symbol Ce and atomic number 58, and is a soft, ductile, and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series, and while it often shows the oxidation state of +3 characteristic of the series, it also has a stable +4 state that does not oxidize water. It is considered one of the rare-earth elements. Cerium has no known biological role in humans but is not particularly toxic, except with intense or continued exposure.

Praseodymium is a chemical element; it has symbol Pr and atomic number 59. It is the third member of the lanthanide series and is considered one of the rare-earth metals. It is a soft, silvery, malleable and ductile metal, valued for its magnetic, electrical, chemical, and optical properties. It is too reactive to be found in native form, and pure praseodymium metal slowly develops a green oxide coating when exposed to air.

Neodymium is a chemical element; it has symbol Nd and atomic number 60. It is the fourth member of the lanthanide series and is considered to be one of the rare-earth metals. It is a hard, slightly malleable, silvery metal that quickly tarnishes in air and moisture. When oxidized, neodymium reacts quickly, producing pink, purple/blue, and yellow compounds in the +2, +3 and +4 oxidation states. It is generally regarded as having one of the most complex spectra of the elements. Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach, who also discovered praseodymium. Neodymium is present in significant quantities in the minerals monazite and bastn??site. Neodymium is not found naturally in metallic form or unmixed with other lanthanides, and it is usually refined for general use. Neodymium is fairly common???about as common as cobalt, nickel, or copper???and is widely distributed in the Earth's crust. Most of the world's commercial neodymium is mined in China, as is the case with many ot

Europium is a chemical element; it has symbol Eu and atomic number 63. It is a silvery-white metal of the lanthanide series that reacts readily with air to form a dark oxide coating. Europium is the most chemically reactive, least dense, and softest of the lanthanides. It is soft enough to be cut with a knife. Europium was discovered in 1896, provisionally designated as ??; in 1901, it was named after the continent of Europe. Europium usually assumes the oxidation state +3, like other members of the lanthanide series, but compounds having oxidation state +2 are also common. All europium compounds with oxidation state +2 are slightly reducing due to their tendency to get oxidised into the more stable +3 state. It has no significant biological role but is relatively non-toxic compared to other heavy metals. Most applications of europium exploit the phosphorescence of europium compounds. Europium is one of the rarest of the rare-earth elements on Earth.

Lanthanum is a chemical element; it has symbol La and atomic number??57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air. It is the first and the prototype of the lanthanide series, a group of 15??similar elements between lanthanum and lutetium in the periodic table. Lanthanum is traditionally counted among the rare-earth elements. Like most other rare-earth elements, its usual oxidation state is +3, although some compounds are known with an oxidation state of +2. Lanthanum has no biological role in humans but is used by some bacteria. It is not particularly toxic to humans but does show some antimicrobial activity.

Promethium is a chemical element; it has symbol Pm and atomic number 61. All of its isotopes are radioactive; it is extremely rare, with only about 500???600 grams naturally occurring in the Earth's crust at any given time. Promethium is one of only two radioactive elements that are both preceded and succeeded in the periodic table by elements with stable forms, the other being technetium. Chemically, promethium is a lanthanide. Promethium shows only one stable oxidation state of +3.

Samarium is a chemical element; it has symbol Sm and atomic number 62. It is a moderately hard silvery metal that slowly oxidizes in air. Being a typical member of the lanthanide series, samarium usually has the oxidation state +3. Compounds of samarium(II) are also known, most notably the monoxide SmO, monochalcogenides SmS, SmSe and SmTe, as well as samarium(II) iodide.

Gadolinium is a chemical element; it has symbol Gd and atomic number 64. It is a silvery-white metal when oxidation is removed. Gadolinium is a ductile and malleable rare-earth element. It reacts with atmospheric oxygen or moisture slowly to form a black oxide coating. Gadolinium below its Curie point of 20????C (68????F) is ferromagnetic, with an attraction to a magnetic field higher than that of nickel. Above this temperature it is the most paramagnetic element. It is found in nature only in an oxidized form. When separated, it usually has impurities of the other rare earths because of their similar chemical properties.

Terbium is a chemical element; it has symbol Tb and atomic number 65. It is a silvery-white, rare earth metal that is malleable and ductile. The ninth member of the lanthanide series, terbium is a fairly electropositive metal that reacts with water, evolving hydrogen gas. Terbium is never found in nature as a free element, but it is contained in many minerals, including cerite, gadolinite, monazite, xenotime and euxenite.

Dysprosium is a chemical element; it has symbol Dy and atomic number 66. It is a rare-earth element in the lanthanide series with a metallic silver luster. Dysprosium is never found in nature as a free element, though, like other lanthanides, it is found in various minerals, such as xenotime. Naturally occurring dysprosium is composed of seven isotopes, the most abundant of which is 164Dy.

Holmium is a chemical element; it has symbol Ho and atomic number 67. It is a rare-earth element and the eleventh member of the lanthanide series of elements. It is a relatively soft, silvery, fairly corrosion-resistant and malleable metal. Like many other lanthanides, holmium is too reactive to be found in native form, as pure holmium slowly forms a yellowish oxide coating when exposed to air. When isolated, holmium is relatively stable in dry air at room temperature. However, it reacts with water and corrodes readily, and also burns in air when heated.

Erbium is a chemical element; it has symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements. It is a lanthanide, a rare-earth element, originally found in the gadolinite mine in Ytterby, Sweden, which is the source of the element's name.

Thulium is a chemical element; it has symbol Tm and atomic number 69. It is the thirteenth element in the lanthanide series of metals. It is the second-least abundant lanthanide in the Earth's crust, after radioactively unstable promethium. It is an easily workable metal with a bright silvery-gray luster. It is fairly soft and slowly tarnishes in air. Despite its high price and rarity, thulium is used as a dopant in solid-state lasers. It has no significant biological role and is not particularly toxic. Artificial radioactive isotopes of thulium are used as radiation sources in some portable X-ray devices.

Ytterbium is a chemical element; it has symbol Yb and atomic number 70. It is a metal, the fourteenth element in the lanthanide series, which is the basis of the relative stability of its +2 oxidation state. Like the other lanthanides, its most common oxidation state is +3, as in its oxide, halides, and other compounds. In aqueous solution, like compounds of other late lanthanides, soluble ytterbium compounds form complexes with nine water molecules. Because of its closed-shell electron configuration, its density, melting point and boiling point are much lower than those of most other lanthanides.

Lutetium is a chemical element; it has symbol Lu and atomic number 71. It is a silvery white metal, which resists corrosion in dry air, but not in moist air. Lutetium is the last element in the lanthanide series, and it is traditionally counted among the rare earth elements; it can also be classified as the first element of the sixth-period transition metals.

Americium is a synthetic chemical element; it has symbol Am and atomic number 95. It is radioactive and a transuranic member of the actinide series in the periodic table, located under the lanthanide element europium and was thus named after the Americas by analogy.

Curium is a synthetic chemical element; it has symbol Cm and atomic number 96. This transuranic actinide element was named after eminent scientists Marie and Pierre Curie, both known for their research on radioactivity. Curium was first intentionally made by the team of Glenn T. Seaborg, Ralph A. James, and Albert Ghiorso in 1944, using the cyclotron at Berkeley. They bombarded the newly discovered element plutonium with alpha particles. This was then sent to the Metallurgical Laboratory at the University of Chicago where a tiny sample of curium was eventually separated and identified. The discovery was kept secret until after the end of World War II. The news was released to the public in November 1947. Most curium is produced by bombarding uranium or plutonium with neutrons in nuclear reactors ??? one tonne of spent nuclear fuel contains ~20 grams of curium.

Berkelium is a synthetic chemical element; it has symbol Bk and atomic number 97. It is a member of the actinide and transuranium element series. It is named after the city of Berkeley, California, the location of the Lawrence Berkeley National Laboratory where it was discovered in December 1949. Berkelium was the fifth transuranium element discovered after neptunium, plutonium, curium and americium.

Californium is a synthetic chemical element; it has symbol Cf and atomic number 98. It was first synthesized in 1950 at Lawrence Berkeley National Laboratory by bombarding curium with alpha particles. It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all elements that have been produced in amounts large enough to see with the naked eye. It was named after the university and the U.S. state of California.

Einsteinium is a synthetic chemical element; it has symbol Es and atomic number 99 and is a member of the actinide series and the seventh transuranium element.

Fermium is a synthetic chemical element; it has symbol Fm and atomic number 100. It is an actinide and the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities, although pure fermium metal has not been prepared yet. A total of 20 isotopes are known, with 257Fm being the longest-lived with a half-life of 100.5 days.

Mendelevium is a synthetic chemical element; it has symbol Md and atomic number 101. A metallic radioactive transuranium element in the actinide series, it is the first element by atomic number that currently cannot be produced in macroscopic quantities by neutron bombardment of lighter elements. It is the thirteenth actinide, the ninth transuranic element, and the first transfermium; it is named after Dmitri Mendeleev, the father of the periodic table.

Nobelium is a synthetic chemical element; it has symbol No and atomic number 102. It is named after Alfred Nobel, the inventor of dynamite and benefactor of science. A radioactive metal, it is the tenth transuranium element, the second transfermium, and is the fourteenth member of the actinide series. Like all elements with atomic number over 100, nobelium can only be produced in particle accelerators by bombarding lighter elements with charged particles. A total of twelve nobelium isotopes are known to exist; the most stable is 259No with a half-life of 58 minutes, but the shorter-lived 255No is most commonly used in chemistry because it can be produced on a larger scale.

Lawrencium is a synthetic chemical element; it has symbol Lr and atomic number 103. It is named after Ernest Lawrence, inventor of the cyclotron, a device used to discover many artificial radioactive elements. A radioactive metal, lawrencium is the eleventh transuranium element, the third transfermium, and the last member of the actinide series. Like all elements with atomic number over 100, lawrencium can only be produced in particle accelerators by bombarding lighter elements with charged particles. Fourteen isotopes of lawrencium are known; the most stable is 266Lr with half-life 11 hours, but the shorter-lived 260Lr is most commonly used in chemistry because it can be produced on a larger scale.

Hydrogen is a chemical element; it has the symbol??H and atomic number??1. It is the lightest and most abundant chemical element in the universe, constituting about 75% of all normal matter. Under standard conditions, hydrogen is a gas of diatomic molecules with the formula??H2, called dihydrogen, or sometimes hydrogen gas, molecular hydrogen, or simply hydrogen. Dihydrogen is colorless, odorless, non-toxic, and highly combustible. Stars, including the Sun, mainly consist of hydrogen in a plasma state, while on Earth, hydrogen is found as the gas??H2 (dihydrogen) and in molecules, such as in water and organic compounds. The most common isotope of hydrogen, 1H, consists of one proton, one electron, and no neutrons.

Helium is a chemical element; it has symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is the lowest among all the elements, and it does not have a melting point at standard pressures. It is the second-lightest and second-most abundant element in the observable universe, after hydrogen. It is present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. Its abundance is similar to this in both the Sun and Jupiter, because of the very high nuclear binding energy of helium-4 with respect to the next three elements after helium. This helium-4 binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay. The most common isotope of helium in the universe is helium-4, the vast majority of which was formed during the Big Bang. Large amounts of new helium are created by nuclear fusion of hydrogen in s

Lithium is a chemical element; it has symbol Li and atomic number??3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid element. Like all alkali metals, lithium is highly reactive and flammable, and must be stored in vacuum, inert atmosphere, or inert liquid such as purified kerosene or mineral oil. It exhibits a metallic luster when pure, but quickly corrodes in air to a dull silvery gray, then black tarnish. It does not occur freely in nature, but occurs mainly as pegmatitic minerals, which were once the main source of lithium. Due to its solubility as an ion, it is present in ocean water and is commonly obtained from brines. Lithium metal is isolated electrolytically from a mixture of lithium chloride and potassium chloride.

Beryllium is a chemical element; it has symbol Be and atomic number 4. It is a steel-gray, hard, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to form minerals. Gemstones high in beryllium include beryl and chrysoberyl. It is a relatively rare element in the universe, usually occurring as a product of the spallation of larger atomic nuclei that have collided with cosmic rays. Within the cores of stars, beryllium is depleted as it is fused into heavier elements. Beryllium constitutes about 0.0004 percent by mass of Earth's crust. The world's annual beryllium production of 220 tons is usually manufactured by extraction from the mineral beryl, a difficult process because beryllium bonds strongly to oxygen.

Boron is a chemical element; it has symbol??B and atomic number??5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the boron group it has three valence electrons for forming covalent bonds, resulting in many compounds such as boric acid, the mineral sodium borate, and the ultra-hard crystals of boron carbide and boron nitride.

Carbon is a chemical element; it has symbol C and atomic number 6. It is nonmetallic and tetravalent???meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 electrons. It belongs to group 14 of the periodic table. Carbon makes up about 0.025 percent of Earth's crust. Three isotopes occur naturally, 12C and 13C being stable, while 14C is a radionuclide, decaying with a half-life of 5,700??years. Carbon is one of the few elements known since antiquity.

Nitrogen is a chemical element; it has symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bond to form N2, a colourless and odourless diatomic gas. N2 forms about 78% of Earth's atmosphere, making it the most abundant chemical species in air. Because of the volatility of nitrogen compounds, nitrogen is relatively rare in the solid parts of the Earth.

Oxygen is a chemical element; it has the symbol??O and its atomic number is??8. It is a member of the chalcogen group in the periodic table. It is highly reactive, a nonmetal, and a potent oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is the most abundant element in Earth's crust, making up almost half of the Earth's crust in the form of various oxides such as water, carbon dioxide, iron oxides, and silicates. It is also the third-most abundant element in the universe after hydrogen and helium.

Fluorine is a chemical element; it has symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as pale yellow diatomic gas. Fluorine is extremely reactive as it reacts with all other elements except for the light noble gases. Fluorine in its elemental form is highly toxic.

Neon is a chemical element; it has the symbol Ne and the atomic number 10. It is the second noble gas in the periodic table. Neon is a colorless, odorless, inert monatomic gas under standard conditions, with approximately two-thirds the density of air.

Sodium is a chemical element; it has symbol??Na and atomic number??11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable isotope is 23Na. The free metal does not occur in nature and must be prepared from compounds. Sodium is the sixth most abundant element in the Earth's crust and exists in numerous minerals such as feldspars, sodalite, and halite (NaCl). Many salts of sodium are highly water-soluble: sodium ions have been leached by the action of water from the Earth's minerals over eons, and thus sodium and chlorine are the most common dissolved elements by weight in the oceans.

Magnesium is a chemical element; it has symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point, and high chemical reactivity. Like the other alkaline earth metals, it occurs naturally only in combination with other elements and almost always has an oxidation state of +2. It reacts readily with air to form a thin passivation coating of magnesium oxide that inhibits further corrosion of the metal. The free metal burns with a brilliant-white light. The metal is obtained mainly by electrolysis of magnesium salts obtained from brine. It is less dense than aluminium and is used primarily as a component in strong and lightweight alloys that contain aluminium.

Aluminium or aluminum is a chemical element; it has symbol??Al and atomic number??13. It has a density lower than other common metals, about one-third that of steel. Aluminium has a great affinity toward oxygen, forming a protective layer of oxide on the surface when exposed to air. It visually resembles silver, both in its color and in its great ability to reflect light. It is soft, nonmagnetic, and ductile. It has one stable isotope, 27Al, which is highly abundant, making aluminium the 12th-most abundant element in the universe. The radioactivity of 26Al leads to it being used in radiometric dating.

Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent non-metal and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, lead, and flerovium are below it. It is relatively unreactive. Silicon is a significant element that is essential for several physiological and metabolic processes in plants. Silicon is widely used as a semiconductor material in various electrical devices such as transistors, solar cells, and integrated circuits. It dominates semiconductor applications due to its low cost, excellent electronic properties, and adaptable physical characteristics.

Francium is a chemical element; it has symbol Fr and atomic number 87. It is extremely radioactive; its most stable isotope, francium-223, has a half-life of only 22??minutes. It is the second-most electropositive element, behind only caesium, and is the second rarest naturally occurring element. Francium's isotopes decay quickly into astatine, radium, and radon. The electronic structure of a francium atom is [Rn] 7s1; thus, the element is classed as an alkali metal.

Phosphorus is a chemical element; it has symbol P and atomic number 15. All elemental forms of phosphorus are highly reactive and are therefore never found in nature. Elemental phosphorus can be prepared artificially, the two most common allotropes being white phosphorus and red phosphorus. With 31P as its only stable isotope, phosphorus has an occurrence in Earth's crust of about 0.1%, generally as phosphate rock. A member of the pnictogen family, phosphorus readily forms a wide variety of organic and inorganic compounds, with as its main oxidation states +5, +3 and ???3.

Iron is a chemical element; it has symbol Fe and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most abundant element in the Earth's crust. In its metallic state it was mainly deposited by meteorites.

Sulfur (American spelling and the preferred IUPAC name) or sulphur (Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with the chemical formula S8. Elemental sulfur is a bright yellow, crystalline solid at room temperature.

Chlorine is a chemical element; it has symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the revised Pauling scale, behind only oxygen and fluorine.

Argon is a chemical element; it has symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third most abundant gas in Earth's atmosphere, at 0.934%. It is more than twice as abundant as water vapor, 23 times as abundant as carbon dioxide, and more than 500 times as abundant as neon. Argon is the most abundant noble gas in Earth's crust, comprising 0.00015% of the crust.

Potassium is a chemical element; it has symbol K and atomic number??19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals, all of which have a single valence electron in the outer electron shell, which is easily removed to create an??ion with a positive charge. In nature, potassium occurs only in ionic salts. Elemental potassium reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, and burning with a lilac-colored flame. It is found dissolved in seawater, and occurs in many minerals such as orthoclase, a common constituent of granites and other igneous rocks.

Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust, and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossils of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name comes from the Latin word calx, which was obtained from heating limestone.

Lead is a chemical element with the symbol Pb and atomic number 82. It is a heavy metal, denser than most common materials. Lead is soft, malleable, and has a relatively low melting point. When freshly cut or melted, it appears shiny silvery with a bluish tint, but tarnishes to dull gray on exposure to air. Lead has the highest atomic number of any stable element, and three of its isotopes are endpoints of major nuclear decay chains of heavier elements.

Scandium is a chemical element; it has symbol Sc and atomic number 21. It is a silvery-white metallic element found in the d-block of the periodic table. Usually, it is classified as a rare-earth element, together with yttrium and the lanthanides. It was discovered in 1879 by spectral analysis of the minerals euxenite and gadolinite from Scandinavia.

Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength that is resistant to corrosion in sea water, aqua regia, and chlorine.

Vanadium is a chemical element; it has symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an oxide layer (passivation) somewhat stabilizes the free metal against further oxidation.

Chromium is a chemical element; it has symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal.

Manganese is a chemical element; it has the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. First isolated in the 1770s, manganese is a transition metal with many industrial alloy uses, particularly in stainless steels in which it improves strength, workability, and resistance to wear. Various manganese oxides are used as oxidising agents, as rubber additives, and in glass making, fertilizers, and ceramics. Manganese sulfate can be used as a fungicide.

Rhenium is a chemical element; it has symbol Re and atomic number 75. It is a silvery-gray, heavy, third-row transition metal in group 7 of the periodic table. With an estimated average concentration of 1 part per billion (ppb), rhenium is one of the rarest elements in the Earth's crust. It has one of the highest melting and boiling points of any element. It resembles manganese and technetium chemically and is mainly obtained as a by-product of the extraction and refinement of molybdenum and copper ores. It can assume a wide variety of oxidation states ranging from ???3 to +7.

Cobalt is a chemical element; it has symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, somewhat brittle, gray metal.

Tungsten is a chemical element which has the symbol W and atomic number 74. It is a metal found naturally on Earth almost exclusively in compounds with other elements. It was identified as a distinct element in 1781 and first isolated as a metal in 1783. Its important ores include scheelite and wolframite, the latter lending the element its alternative name.

Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slow to react with air under standard conditions because a passivation layer of nickel oxide that prevents further corrosion forms on the surface. Even so, pure native nickel is found in Earth's crust only in tiny amounts, usually in ultramafic rocks, and in the interiors of larger nickel???iron meteorites that were not exposed to oxygen when outside Earth's atmosphere.

Osmium is a chemical element; it has symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group. Osmium has the highest density of any stable element and one of the lowest abundances in the Earth's crust. Manufacturers use alloys of osmium with platinum, iridium, and other platinum-group metals for fountain pen nib tipping, electrical contacts, and other applications that require extreme durability and hardness.

Copper is a chemical element; it has symbol Cu and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement.

Zinc is a chemical element; it has symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny blue whitish appearance when surface oxidation is removed. It is the first element in group 12 (IIB) of the periodic table. Zinc is the 24th most abundant element in Earth's crust, with an average concentration of 70 grams per ton. Zinc also has five stable isotopes; the most abundant of which, Zn-64, comprises nearly half of zinc's total abundance. In some respects, zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn2+ and Mg2+ ions are of similar size. The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral. The largest concentration of economically feasible lodes in descending order are located in China, Peru, and Australia and among others. Zinc is refined industrially by froth flotation of the ore, roasting, and final extraction using electricity (electrowinning).

Gallium is a chemical element; it has symbol Ga and atomic number 31. Discovered by the French chemist Paul-??mile Lecoq de Boisbaudran in Paris, France, 1875, elemental gallium is a soft, silvery metal at standard temperature and pressure with a complex orthorhombic crystal structure. In its liquid state, it becomes silvery white. If enough force is applied, solid gallium may fracture conchoidally. Gallium does not occur as a free element in nature, but rather as gallium(III) compounds in trace amounts in zinc ores and in bauxite.

Germanium is a chemical element; it has symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid in the carbon group that is chemically similar to silicon. Like silicon, germanium naturally reacts and forms complexes with oxygen in nature.

Arsenic is a chemical element; it has the symbol As and atomic number??33. It is a metalloid and one of the pnictogens, and therefore shares many properties with its group 15 neighbors phosphorus and antimony. Arsenic is notoriously toxic. It occurs naturally in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. It has various allotropes, but only the grey form, which has a metallic appearance, is important to industry.

Selenium is a chemical element; it has symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elemental state or as pure ore compounds in Earth's crust. Selenium was discovered in 1817 by J??ns Jacob Berzelius, who noted the similarity of the new element to the previously discovered tellurium.

Iridium is a chemical element; it has the symbol Ir and atomic number 77. This very hard, brittle, silvery-white transition metal of the platinum group is considered the second-densest naturally occurring metal, with a density of 22.56??g/cm3 (0.815??lb/cu??in) as defined by experimental X-ray crystallography. 191Ir and 193Ir are the only two naturally occurring isotopes of iridium, as well as the only stable isotopes; the latter is the more abundant. It is one of the most corrosion-resistant metals, even at temperatures as high as 2,000????C (3,630????F).

Bromine is a chemical element; it has symbol Br and atomic number 35. It is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between those of chlorine and iodine. Isolated independently by two chemists, Carl Jacob L??wig and Antoine J??r??me Balard, its name was derived from Ancient Greek ????????????? (bromos) 'stench', referring to its sharp and pungent smell.

Platinum is a chemical element; it has symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name originates from Spanish platina, a diminutive of plata "silver".

Krypton is a chemical element; it has symbol Kr and atomic number 36. It is a colorless, odorless noble gas that occurs in trace amounts in the atmosphere and is often used with other rare gases in fluorescent lamps. Krypton is chemically inert.

Rubidium is a chemical element; it has symbol Rb and atomic number 37. It is a very soft, whitish-grey solid in the alkali metal group, similar to potassium and caesium. Rubidium is the first alkali metal in the group to have a density higher than water. On Earth, natural rubidium comprises two isotopes: 72% is a stable isotope 85Rb, and 28% is slightly radioactive 87Rb, with a half-life of 48.8??billion years ??? more than three times as long as the estimated age of the universe.

Gold is a chemical element; its chemical symbol is Au and atomic number 79. In its pure form, it is a bright-metallic-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal, a group 11 element, and one of the noble metals. It is one of the least reactive chemical elements, being the second lowest in the reactivity series, with only platinum ranked as less reactive. Gold is solid under standard conditions.

Mercury is a chemical element; it has symbol Hg and atomic number 80. It is commonly known as quicksilver. A heavy, silvery d-block element, mercury is the only metallic element that is known to be liquid at standard temperature and pressure. As well as having the lowest freezing point, mercury has the lowest boiling point and subsequently the narrowest liquid state range of any metal at standard conditions.

Thallium is a chemical element; it has symbol Tl and atomic number 81. It is a silvery-white post-transition metal that is not found free in nature. When isolated, thallium resembles tin, but discolors when exposed to air. Chemists William Crookes and Claude-Auguste Lamy discovered thallium independently in 1861, in residues of sulfuric acid production. Both used the newly developed method of flame spectroscopy, in which thallium produces a notable green spectral line. Thallium, from Greek ????????????, thall??s, meaning "green shoot" or "twig", was named by Crookes. It was isolated by both Lamy and Crookes in 1862, Lamy by electrolysis and Crookes by precipitation and melting of the resultant powder. Crookes exhibited it as a powder precipitated by zinc at the International Exhibition, which opened on 1 May that year.

Strontium is a chemical element; it has symbol Sr and atomic number 38. An alkaline earth metal, it is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is exposed to air. Strontium has physical and chemical properties similar to those of its two vertical neighbors in the periodic table, calcium and barium. It occurs naturally mainly in the minerals celestine and strontianite, and is mostly mined from these.

Yttrium is a chemical element; it has symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and has often been classified as a rare-earth element. Yttrium is almost always found in combination with lanthanide elements in rare-earth minerals and is never found in nature as a free element. 89Y is the only stable isotope and the only isotope found in the Earth's crust.

Bismuth is a chemical element; it has symbol Bi and atomic number 83. It is a post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth occurs naturally, and its sulfide and oxide forms are important commercial ores. The free element is 86% as dense as lead. It is a brittle metal with a silvery-white color when freshly produced. Surface oxidation generally gives samples of the metal a somewhat rosy cast. Further oxidation under heat can give bismuth a vividly iridescent appearance due to thin-film interference. Bismuth is the most diamagnetic element and of all the metals, it is among the most electrically resistive and least thermally conductive known.

Polonium is a chemical element; it has symbol Po and atomic number 84. A rare and highly radioactive metal with no stable isotopes, polonium is a chalcogen and chemically similar to selenium and tellurium, though its metallic character resembles that of its horizontal neighbours in the periodic table: thallium, lead, and bismuth. Due to the short half-life of all its isotopes, its natural occurrence is limited to tiny traces of the fleeting polonium-210 in uranium ores, as it is the penultimate daughter of natural uranium-238. Though two longer-lived isotopes exist, they are much more difficult to produce. Today, polonium is usually produced in milligram quantities by the neutron irradiation of bismuth. Due to its intense radioactivity, which results in the radiolysis of chemical bonds and radioactive self-heating, its chemistry has mostly been investigated on the trace scale only.

Astatine is a chemical element; it has symbol At and atomic number 85. It is the rarest naturally occurring element in the Earth's crust, occurring only as the decay product of various heavier elements. All of astatine's isotopes are short-lived; the most stable is astatine-210, with a half-life of 8.1 hours. Consequently, a solid sample of the element has never been seen, because any macroscopic specimen would be immediately vaporized by the heat of its radioactivity.

Lobamba is a town in Eswatini located in between Eswatini's two main cities, Mbabane and Manzini.

Belfast is the capital city and principal port of the North Of Ireland standing on the banks of the River Lagan and connected to the open sea through Belfast Lough and the North Channel. It is the largest city in Northern Ireland and the second-largest city in Ireland, with an estimated population of 352,390 in 2024, and its metropolitan area has a population of 704,406.

Georgetown is the capital and largest city of Guyana. It is situated in Demerara-Mahaica, region 4, on the Atlantic Ocean coast, at the mouth of the Demerara River. It is nicknamed the "Garden City of the Caribbean". It is the retail, administrative, and financial services centre of the country, and the city accounts for a large portion of Guyana's GDP. The city recorded a population of 125,683 as of 2022 census.

Prague is the capital and largest city of the Czech Republic and the historical capital of Bohemia. Located on the Vltava River, the city has a population of about 1.4 million, making it the twelfth-largest city in the European Union. Its metropolitan area is home to approximately 2.3 million people.

Sarajevo is the capital and largest city of Bosnia and Herzegovina, with a population of 275,524 in its administrative limits. The Sarajevo Canton, containing the city of Sarajevo and nearby municipalities, is home to 413,593 inhabitants. Located within the greater Sarajevo valley of Bosnia, it is surrounded by the Dinaric Alps and situated along the Miljacka River in the heart of the Balkans, a region of Southeastern Europe.

Ciudad de la Paz, previously known as Djibloho or Oyala, commonly known as La Paz, is the capital city of Equatorial Guinea, having replaced Malabo on 2 January 2026. Established as an urban district in Wele-Nzas in 2015, it is also the administrative headquarters of Djibloho, Equatorial Guinea's newest province created in 2017, and is located near the town of Mengomey??n. In 2017, the city was officially named Ciudad de la Paz.

Jerusalem is a city in the Southern Levant, on a plateau in the Judaean Mountains between the Mediterranean and the Dead Sea. It is one of the oldest cities in the world and is considered holy to the three major Abrahamic religions: Judaism, Christianity and Islam. Both Israel and Palestine claim Jerusalem as their capital city; Israel maintains its primary governmental institutions there, while Palestine ultimately foresees it as its seat of power. Neither claim is widely recognised internationally.

Majuro is the capital and largest city of the Marshall Islands. It is also a large coral atoll of 64 islands in the Pacific Ocean. It forms a legislative district of the Ratak (Sunrise) Chain of the Marshall Islands. The atoll has a land area of 9.7 square kilometers (3.7??sq??mi) and encloses a lagoon of 295 square kilometers (114??sq??mi). As with other atolls in the Marshall Islands, Majuro consists of narrow land masses. It has a tropical trade wind climate, with an average temperature of 27????C (81????F).

South Tarawa is the capital and hub of the Republic of Kiribati and home to more than half of Kiribati's population. The South Tarawa population centre consists of all the small islets from Betio in the west to Bonriki and Tanaea in the north-east, connected by the South Tarawa main road, with an approximate population of 73,073 as of 2026.

Oranjestad, the capital and most populous of Aruba's eight regions, is located on the southwestern coast of the island. In Papiamento, the local language, Oranjestad is commonly referred to as "Playa" by the locals.

Large urban area on Lake Managua, part of the Municipality of Managua, Nicaragua.

Aden is an ancient port city in the southern part of the Arabian peninsula, on the north coast of the Gulf of Aden, positioned near the eastern approach to the Red Sea, and has been the de facto capital of Yemen since 2014. It is approximately 170??km (110??mi) east of the Bab-el-Mandeb strait. With its strategic location on the coastline, Aden serves as a gateway between the Red Sea and the Arabian Sea, making it a crucial maritime hub connecting Africa, Asia, and the Middle East.

Willemstad is the capital and largest city of Cura??ao, an island in the southern Caribbean Sea that is a constituent country of the Kingdom of the Netherlands. It was the capital of the Netherlands Antilles prior to that entity's dissolution in 2010. The city counts to have around 90% of Cura??ao's population, with 136,660 inhabitants as of 2011. The historic centre of the city consists of four quarters: the Punda and Otrobanda, which are separated by the Sint Anna Bay, an inlet that leads into the large natural harbour called the Schottegat, as well as the Scharloo and Pietermaai Smal quarters, which are across from each other on the smaller Waaigat harbour. Willemstad is home to the Cura??ao synagogue, the oldest surviving synagogue in the Americas. The city centre, with its unique architecture and harbour entry, has been designated a UNESCO World Heritage Site.

Montevideo is the capital and largest city of Uruguay. As of the 2023 census, the city proper has a population of 1,287,452, making up about 36.8% of the country's total population, in an area of 201 square kilometers (78??sq??mi). Montevideo is situated on the southern coast of the country, on the northeastern bank of the R??o de la Plata.

Dhaka, formerly known as Dacca, is the capital and largest city of Bangladesh. With an estimated population of 36.6 million, Dhaka is the second largest city by population in the world, and is widely considered to be the most densely populated built-up urban area in the world. Dhaka is an important cultural, economic, and scientific hub of Eastern South Asia with its most affluent neighborhood Gulshan being among the wealthiest neighborhoods in South Asia. Dhaka ranks fourth in South Asia and 55th in the world in terms of GDP. Lying on the Ganges Delta, it is bounded by the Buriganga, Turag, Dhaleshwari and Shitalakshya rivers. It is also the largest Bengali-speaking city in the world.

Islamabad is the capital city of Pakistan. It is the country's tenth-most populous city with a population of over 1.1 million; and is federally administered by the Pakistani government as part of the Islamabad Capital Territory ??? with a metropolitan population of over 2.3 million. Built as a planned city in the 1960s and established in 1967 along the Margalla Hills, Islamabad replaced Karachi as Pakistan's national capital. It is located north of the city of Rawalpindi, the largest in northern Punjab, with which it forms a metropolitan area of over 5.7 million inhabitants.

Gibraltar is a British Overseas Territory and city located at the southern tip of the Iberian Peninsula, on the Bay of Gibraltar, near the exit of the Mediterranean Sea into the Atlantic Ocean. It has an area of 6.8??km2 (2.6??sq??mi) and is bordered to the north by Spain. The landscape is dominated by the Rock of Gibraltar, at the foot of which is a densely populated town area. Gibraltar is home to around 34,000 people, primarily Gibraltarians.

Zagreb is the capital and largest city of Croatia. It is in the north of the country, along the Sava river, at the southern slopes of the Medvednica mountain. Zagreb stands near the international border between Croatia and Slovenia at an elevation of approximately 158??m (518??ft) above sea level. At the 2021 census, the city itself had a population of 767,131, while the population of Zagreb metropolitan area is 1,086,528.

Manila, officially the City of Manila, is the capital and second-most populous city of the Philippines after Quezon City. According to the 2024 census, it has a population of 1,902,590 people. Located on the eastern shore of Manila Bay on the island of Luzon, it is classified as a highly urbanized city. With 44,935 inhabitants per square kilometer (116,380/sq??mi), Manila is one of the world's most densely populated cities proper.

Buenos Aires, officially the Autonomous City of Buenos Aires, is the capital and largest city of Argentina. It is located on the southwest of the R??o de la Plata. Buenos Aires is classified as an Alpha??? global city, according to the GaWC 2024 ranking. The city proper has a population of 3.1 million and its urban area has a population of 16.7 million, making it the 21st most populous metropolitan area in the world.

Mexico City is the capital and most populous city of Mexico, as well as the most populous city in North America. It is one of the most important cultural and financial centers in the world, and is classified as an Alpha world city according to the Globalization and World Cities Research Network (GaWC) 2024 ranking. Mexico City is located in the Valley of Mexico within the high Mexican central plateau, at an altitude of 2,240 meters. The city has 16 boroughs or demarcaciones territoriales, which are in turn divided into neighborhoods or colonias.

Tokyo, officially the Tokyo Metropolis, is the capital and most populous city of Japan. The population of the city proper was over 14 million as of 2023. The Greater Tokyo Area, which includes Tokyo and parts of six neighboring prefectures, is the third-most populous metropolitan area in the world, with 33 million residents as of 2025.

La Paz, officially Nuestra Se??ora de La Paz is the seat of government of Bolivia. With 755,732 residents as of 2024, it is the third-most populous city in Bolivia. Its metropolitan area, which includes the neighboring city of El Alto, and other smaller towns, is the second most populous urban area in Bolivia, with a population of 2.2??million, after Santa Cruz de la Sierra with a population of 2.3??million. The city is also the capital of the department of the same name.

Abu Dhabi is the capital city of the United Arab Emirates (UAE). The city is the seat of the Abu Dhabi Central Capital District, the capital city of the Emirate of Abu Dhabi, and the UAE's second-most populous city, after Dubai. The city is situated on a T-shaped island, extending into the Persian Gulf from the central-western coast of the UAE.

Astana is the capital city of Kazakhstan. With a population of 1,622,245 within the city limits, it is the second-largest in the country after Almaty, the national capital until 1997. The city lies on the banks of the Ishim river in the north of Kazakhstan and is located within the Akmola Region but is self-administering. Initially founded as Aqmoly in 1830, the city was later renamed Akmolinsk, Tselinograd, and Aqmola before adopting the name Astana in 1998, or "capital" in Kazakh. In 2019, the city briefly adopted the name Nur-Sultan in honor of former president Nursultan Nazarbayev, but it reverted to the name Astana in 2022.

Athens is the capital and largest city of Greece. A significant coastal urban area in the Mediterranean, Athens is also the capital of the Attica region and is the southernmost capital on the European mainland. With its urban area's population numbering over 3.6 million, it is the eighth-largest urban area in the European Union (EU). The Municipality of Athens, which constitutes a small administrative unit of the entire urban area, had a population of 643,452 in 2021, within its official limits, and a land area of 38.96 square kilometres.

Baghdad is the capital and largest city in Iraq. It is located on the banks of the Tigris in central Iraq. The city has an estimated population of 8 million. It ranks among the most populous and largest cities in the Middle East and the Arab world and constitutes 22% of Iraq's population. Baghdad is a primary financial and commercial center in the region.

Caracas, officially Santiago de Le??n de Caracas (CCS), is the capital and largest city of Venezuela, and the center of the Metropolitan Region of Caracas. Caracas is located along the Guaire River in the northern part of Venezuela, within the Caracas Valley of the Venezuelan coastal mountain range. The valley is close to the Caribbean Sea, separated from the shore by a steep 2,200-meter-high (7,200-foot) mountain range, Cerro El ??vila. To the south there are more hills and mountains that form the valley. The Metropolitan Region of Caracas has an estimated population of over 5 million inhabitants.

Guatemala City, also known colloquially by the nickname Guate, is the national capital and largest city of the Republic of Guatemala. It serves as the municipal capital of the surrounding Guatemala Department. Its metropolitan area is also the largest in Central America. The city is located in a mountain valley called Valle de la Ermita in the south-central part of the country.

Havana is the capital and largest city of Cuba. The heart of La Habana Province, Havana is the country's main port and commercial center. It is the most populous city, the largest by area, and the second-largest metropolitan area in the Caribbean region. The population in 2021 was 2,142,939 inhabitants, and its area is 728.26??km2 (281.18??sq??mi) for the capital city and 8,475.57??km2 for the metropolitan zone. Its official population however had dropped to 1,749,964 inhabitants by the end of 2024.

Ramallah is a city in the central West Bank, Palestine. It serves as the administrative capital of Palestine, as well as capital of the Ramallah and al-Bireh Governorate. The city is situated on the Judaean Mountains, 10??km north of Jerusalem, at an average elevation of 872 meters (2,861??ft) above sea level, adjacent to al-Bireh.

Gitega, formerly Kitega, is the political capital of Burundi. Located in the centre of the country, in the Burundian central plateau roughly 62 kilometres (39??mi) east of Bujumbura, the largest city and former political capital, Gitega is the country's fourth largest city and former royal capital of the Kingdom of Burundi until its abolition in 1966. In December 2018, former President of Burundi Pierre Nkurunziza announced that he would follow on a 2007 promise to return Gitega its former political capital status, with Bujumbura remaining as economic capital and centre of commerce. A vote in the Parliament of Burundi made the change official on 16 January 2019, with all branches of government expected to move in over three years.

Hargeisa is the capital and largest city of the Republic of Somaliland, a partially recognised sovereign state in the Horn of Africa, still considered internationally to be part of Somalia. It is also the regional capital of the Maroodi Jeex region of Somaliland.

Vienna is the capital, most populous city, and one of the nine states of Austria. It is Austria's primate city, with just over two million inhabitants. Its larger metropolitan area has a population of nearly 2.9??million, representing nearly one-third of the country's population. Vienna is the cultural, economic, and political centre of the country, the fifth-largest city by population in the European Union, and the most populous of the cities on the river Danube.

Copenhagen is the capital and most populous city of both the country of Denmark and the wider Kingdom of Denmark, with a population of 671,673 people in the municipality and 1.4 million in the urban area. The city is situated mainly on the island of Zealand (Sj??lland), with a smaller part on the island of Amager. Copenhagen is separated from Malm??, Sweden, by the ??resund strait. The ??resund Bridge connects the two cities by rail and road.

Stockholm is the capital and most populous city of Sweden, as well as the largest urban area in the Nordic countries. Approximately 1 million people live in the municipality, with 1.6??million in the urban area, and 2.5??million in the metropolitan area. The city stretches across fourteen islands where Lake M??laren flows into the Baltic Sea. Outside the city to the east, and along the coast, is the island chain of the Stockholm archipelago. The area has been settled since the Stone Age, in the 6th millennium BC, and was founded as a city in 1252 by Swedish statesman Birger Jarl. The city serves as the county seat of Stockholm County.

Helsinki, until about 1930 known in English by its Swedish name of Helsingfors, is the capital and most populous city in Finland. It is on the shore of the Gulf of Finland and is the seat of southern Finland's Uusimaa region. About 694,000 people live in the municipality, with 1.3??million in the capital region and 1.6??million in the metropolitan area. As the most populous urban area in Finland, it is the country's most significant centre for politics, education, finance, culture, and research. Helsinki is 80 kilometres (50??mi) north of Tallinn, Estonia, 400 kilometres (250??mi) east of Stockholm, Sweden, and 300 kilometres (190??mi) west of Saint Petersburg, Russia.

Dublin is the capital and largest city of Ireland. Situated on Dublin Bay at the mouth of the River Liffey, it is in the province of Leinster, and is bordered on the south by the Dublin Mountains, part of the Wicklow Mountains range. Dublin is the largest city by population on the island of Ireland; at the 2022 census, the city council area had a population of 592,713, while the city, including suburbs, had a population of 1,263,219, and County Dublin had a population of 1,501,500. Various definitions of a metropolitan Greater Dublin Area exist.

Reykjav??k is the capital and largest city of Iceland. It is located on the southern shore of the Faxafl??i bay in southwest Iceland and has a latitude of 64??08??? N, making it the world's northernmost capital of a sovereign state. Reykjav??k has a population of around 139,000 as of 2025, and the surrounding Capital Region has a population of around 249,000, constituting approximately 64% of Iceland's population.

Tallinn is the capital and most populous city of Estonia. Located on a bay in northern Estonia, on the shore of the Gulf of Finland of the Baltic Sea, it has a population of 460,584 as of 2026 and administratively lies in Harju County. As of 2024, the population of the Tallinn metropolitan area is estimated at 646,315. Tallinn is the main governmental, financial, industrial, and cultural centre of Estonia. It is located 187 kilometres (116??mi) northwest of the country's second largest city, Tartu, however, only 80 kilometres (50??mi) south of Helsinki, Finland. It is also 320 kilometres (200??mi) west of Saint Petersburg, Russia, 300 kilometres (190??mi) north of Riga, Latvia, and 380 kilometres (240??mi) east of Stockholm, Sweden. From the 13th century until the first half of the 20th century, Tallinn was known in most of the world by variants of its other historical name, Reval.

Riga is the capital, primate, and largest city of Latvia and the second largest in the Baltics. Home to 591,882 inhabitants, the city accounts for a third of Latvia's total population. The population of Riga metropolitan area, which stretches beyond the city limits, is estimated at 847,162. The city lies on the Gulf of Riga at the mouth of the Daugava river where it meets the Baltic Sea. Riga's territory covers 307.17??km2 (118.60??sq??mi) and lies 1???10??m (3???33??ft) above sea level on a flat and sandy plain.

Bratislava is the capital and largest city of Slovakia and the fourth largest of all cities on the river Danube. Officially, the population of the city proper is about 479,000, the wider Bratislava Region exceeds 732,000 inhabitants. The metropolitan area has a population of approximately 1.3 million.

Budapest is the capital and most populous city of Hungary. It is Hungary's primate city with 1.7 million inhabitants and its greater metro area has a population of about 3.3 million, representing one-third of the country's population and producing more than 40% of the country's economic output. Budapest is the political, economic, and cultural center of the country, among the ten largest cities in the European Union and the second largest urban area in Central and Eastern Europe. Budapest stands on the River Danube and is strategically located at the center of the Pannonian Basin, lying on ancient trade routes linking the hills of Transdanubia with the Great Plain.

Luxembourg, also known as Luxembourg City, is the capital city of Luxembourg and the country's most populous commune. Standing at the confluence of the Alzette and P??trusse rivers in southern Luxembourg, the city lies in the center of Western Europe, situated 213??km (132??mi) by road from Brussels and 209??km (130??mi) from Cologne. The city contains Luxembourg Castle, established by the Franks in the Early Middle Ages, around which a settlement developed.

The City of San Marino, also known simply as San Marino and locally as Citt??, is the capital city of the Republic of San Marino and one of its nine castelli. It has a population of 4,118. It is on the western slopes of San Marino's highest point, Monte Titano. It is also the fifth-least-populated national capital in the world.

Phnom Penh is the capital and most populous city of Cambodia. It has been the national capital since 1865 and has grown to become the nation's primate city and its political, economic, industrial, and cultural centre. The city's name derives from Wat Phnom, a Buddhist temple, and Lady Penh, the city's founder. It sits at the confluence of the Tonl?? Sap and Mekong rivers, and is the start of the Bassac River. It is also the seat of Cambodia's monarchy, based at the Royal Palace.

Hanoi is the capital and second-most populous municipality of Vietnam. It encompasses an area of 3,358.6??km2 (1,296.8??mi2), and as of 2025 has a population of 8,807,523. Hanoi had the second-highest gross regional domestic product of all Vietnamese provinces and municipalities at US$48 billion in 2023, behind Ho Chi Minh City. It hosts 78 foreign embassies, the headquarters of the Vietnam People's Army (VPA), its Vietnam National University system, and other governmental organizations. Hanoi has 18.7 million domestic and international visitors in 2022. It hosts the Imperial Citadel of Th??ng Long, Ho Chi Minh Mausoleum, Ho??n Ki???m Lake, West Lake, and Ba V?? National Park near the outskirts of the municipality. Hanoi's urban area has architectural styles, including French colonial architecture, brutalist apartments and disorganized alleys and tube houses stemming from the city's growth in the 20th century.

Bangkok, officially known in Thai as Krung Thep Maha Nakhon and colloquially as Krung Thep, is the capital and most populous city of Thailand. The city occupies 1,568.7 square kilometres (605.7??sq??mi) in the Chao Phraya River delta in central Thailand and has an estimated population of 11.4 million people as of 2024, 15.9% of the country's population. Over 17.4??million people live within the surrounding Bangkok Metropolitan Region as of the 2021 estimate, making Bangkok a megacity and an extreme primate city, dwarfing Thailand's other urban centres in both size and importance to the national economy.

Andorra la Vella is the capital and largest city of Andorra. It is located high in the east Pyrenees, between France and Spain. It is also the name of the Andorran parish that surrounds the capital.

Kuala Lumpur (KL), officially the Federal Territory of Kuala Lumpur, is the capital city and a federal territory of Malaysia. It is the most populous city in the country, covering an area of 243??km2 (94??sq??mi) with a population of 2,075,600 as of 2024. Greater Kuala Lumpur, which itself includes the Klang Valley, is an urban agglomeration of 8.81 million people as of 2024. It is among the fastest growing metropolitan regions in Southeast Asia, in terms of both population and economic development.

Taipei, officially Taipei City, is the capital and a special municipality of Taiwan. Located in Northern Taiwan, Taipei City is an enclave of the municipality of New Taipei City that sits about 25 kilometres (16??mi) southwest of the northern port city of Keelung. Most of the city rests on the Taipei Basin, an ancient lakebed. The basin is bounded by the relatively narrow valleys of the Keelung and Xindian rivers, which join to form the Tamsui River along the city's western border.

Pyongyang is the capital and largest city of North Korea. According to the 2008 population census, it has a population of 3,255,288. Pyongyang is located on the Taedong River about 109 kilometers upstream from its mouth on the Yellow Sea. Pyongyang is a directly administered city with a status equal to that of the North Korean provinces.

Kyiv, also Kiev, is the capital and most populous city of Ukraine. Located in the north-central part of the country, it straddles both banks of the Dnieper River. As of January 2022, the population of Kyiv was 2,952,301, making it the seventh-most populous city in Europe. Kyiv is an important industrial, scientific, educational, and cultural center. It is home to high-tech industries, higher education institutions, and historical landmarks. The city has an extensive public transport system, which includes the Kyiv Metro.

Ottawa is the capital city of Canada. It is located in the southeastern portion of the province of Ontario, at the confluence of the Ottawa River and the Rideau River. Ottawa borders Gatineau, Quebec, and forms the core of the Ottawa???Gatineau census metropolitan area (CMA) and the National Capital Region (NCR). As of 2021, Ottawa had a city population of 1,017,449 and a metropolitan population of 1,488,307, making it the fourth-largest city and fourth-largest metropolitan area in Canada.

Juba is the capital and largest city of South Sudan. The city is situated on the White Nile and also serves as the capital of the Central Equatoria State. It is the most recently declared national capital and had a population of 525,953 in 2017. It has an area of 52??km2 (20??sq??mi), with the metropolitan area covering 336??km2 (130??sq??mi).

Yerevan is the capital and largest city of Armenia, as well as one of the world's oldest continuously inhabited cities. Situated along the Hrazdan River, Yerevan is the administrative, cultural, and industrial centre of the country, as its primate city. It has been the capital since 1918, the fourteenth in the history of Armenia and the seventh located in or around the Ararat Plain. The city also serves as the seat of the Araratian Pontifical Diocese, which is the largest diocese of the Armenian Apostolic Church and one of the oldest dioceses in the world.

Khartoum, also spelled Khartum, is the capital city of Sudan as well as Khartoum State. With an estimated population of 7.1 million people, Greater Khartoum is the largest urban area in Sudan.

Bucharest is the capital and largest city of Romania. The metropolis stands on the River D??mbovi??a in south-eastern Romania. Its population is officially estimated at 1.71 million residents within a greater metropolitan area of 2.31 million residents, which makes Bucharest the 9th most-populous city by population within city limits in the European Union. The city has an area of 240??km2 (93??sq??mi), while the metropolitan area covers 1,811??km2 (699??sq??mi). The city proper is administratively known as the "Municipality of Bucharest", and has the same administrative level as that of a national county, being further subdivided into six sectors, each governed by a local mayor. Bucharest is a major cultural, political and economic hub, the country's seat of government, and the capital of the Muntenia region. It is an enclave completely surrounded by Ilfov County.

Tirana is the capital and largest city of Albania. It is located in the centre of the country, enclosed by mountains and hills, with Dajti rising to the east and a slight valley to the northwest overlooking the Adriatic Sea in the distance. It is among the wettest and sunniest cities in Europe, with 2,544 hours of sun per year.

Chi??in??u is the capital and largest city of Moldova. The city is Moldova's main industrial and commercial centre. It is situated in the middle of the country, on the river B??c, a tributary of the Dniester. According to the results of the 2024 Moldovan census, the population of the city proper stood at over 567,000 inhabitants, while the population of the Municipality of Chi??in??u numbered over 720,000 people. Chi??in??u is the most economically prosperous locality in Moldova and the country's largest transport hub. Nearly a third of Moldova's population resides in the metropolitan area.

Vilnius is the capital of and largest city in Lithuania and the most-populous city in the Baltic states. The city's estimated January 2026 population was 617,984, and the Vilnius urban area has an estimated population of 767,907.

Rome is the capital city and most populated comune (municipality) of Italy. It is also the administrative centre of the Lazio region and of the Metropolitan City of Rome. A special comune named Roma Capitale with a population of 2.7 million in an area of 1,287.36??km2 (497.1??mi2), Rome is the third most populous city in the European Union by population within city limits. The Metropolitan City of Rome Capital, with a population of 4.2 million, is the most populous metropolitan city in Italy. Its metropolitan area is the third-most populous within Italy. Rome is located in the central-western portion of the Italian Peninsula, within Lazio (Latium), along the shores of the Tiber Valley. Vatican City is an independent country inside the city boundaries of Rome, the only existing example of a country within a city. Rome is often referred to as the "City of Seven Hills" due to its geography, and also as the "Eternal City". Rome is generally considered to be one of the cradles of Western civilization and Western C

Nuuk is the capital and most populous city of Greenland, an autonomous territory of Denmark. It is the seat of the Sermersooq municipality and the government of Greenland and is the territory's largest cultural and economic center. In January 2025, it had a population of 20,113???more than a third of the territory's population???making it one of the smallest capital cities in the world by population.

Minsk is the capital and largest city of Belarus, located on the Svislach and the now subterranean Nyamiha rivers. As the capital, Minsk has a special administrative status in Belarus and is the administrative centre of Minsk region and Minsk district. As of 2026, it has a population of about two million, making Minsk the 11th-most populous city in Europe. Minsk is one of the administrative capitals of the Commonwealth of Independent States (CIS) and the Eurasian Economic Union (EAEU).

Ulaanbaatar is the capital and most populous city of Mongolia. It has a population of 1.67??million, and is the coldest capital city in the world by average yearly temperature. The municipality is located in north central Mongolia at an elevation of about 1,300 metres (4,300??ft) in a valley on the Tuul River and at the southwestern edge of the Khentii Mountains. Khara T??ne of Tuul River(Mongolian: ???????????? ?????? ????????), the Orda of Toghrul Khan, served as an important alliance centre between the Khamag Mongol Khanate and Keraites during the 12th century.The city was founded in 1639 as a nomadic Buddhist monastic centre, changing location 29 times, and was permanently settled at its modern location in 1778.

Ashgabat is the capital and largest city of Turkmenistan. It lies between the Karakum Desert and the K??petdag mountain range in Central Asia, approximately 50??km (30??mi) away from the Iran-Turkmenistan border. The city has a population of 1,030,063.

Podgorica, formerly known as Titograd from 1946 to 1992 is the capital and largest city of Montenegro. The city is just north of Lake Skadar and close to coastal destinations on the Adriatic Sea. Historically, it was Podgorica's position at the confluence of the Ribnica and Mora??a rivers and at the meeting-point of the fertile Zeta Plain and Bjelopavli??i Valley that encouraged settlement. The surrounding landscape is predominantly mountainous terrain.

Wellington is the capital city of New Zealand. It is located at the southwestern tip of the North Island, between Cook Strait and the Remutaka Range. Wellington is the third-largest city in New Zealand, and is the administrative centre of the Wellington Region. It is the world's southernmost capital of a sovereign state. Wellington features a temperate maritime climate, and is the world's windiest city by average wind speed.

Valletta, also known as Citt?? Umilissima, is the capital city of Malta and one of its 68 council areas. Located between the Grand Harbour to the east and Marsamxett Harbour to the west, its population as of 2021 was 5,157. As Malta's capital city, it is a commercial centre for shopping, bars, dining, and caf?? life. It is also the southernmost capital of Europe, and, at just 0.61 square kilometres (0.24??sq??mi), it is the European Union's smallest capital city.

The City of Brussels is the largest municipality and historical centre of the Brussels-Capital Region, as well as the capital of the French Community of Belgium, the Flemish Region, and Belgium. The City of Brussels is also the administrative centre of the European Union, as it hosts a number of principal EU institutions in its European Quarter.

Brussels, officially the Brussels-Capital Region, is a region of Belgium comprising 19 municipalities, including the City of Brussels, which is the capital of Belgium. The Brussels-Capital Region is located in the central portion of the country. It is a part of both the French Community of Belgium and the Flemish Community, and is separate from the Flemish Region (Flanders), within which it forms an enclave, and the Walloon Region (Wallonia), located less than 4??km (2.5??mi) south.