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Caesium - Barium - Lanthanum

Full table
Name, Symbol, NumberBarium, Ba, 56
Seriesalkaline earth metals
Group, Period, Block2(IIA), 6, s
Density, Hardness3510 kg/m3, 1.25
Appearancesilvery white
Atomic Properties
Atomic weight137.327 amu
Atomic radius (Calc.)215 pm (253 pm)
Covalent radius198 pm
van der Waals radiusno information
Electron configuration [Xe]6s2
e- 's per energy level2, 8, 18, 18, 8, 2
Oxidation states (Oxide)2 (strong base)
Crystal structureCubic body centered
Physical Properties
State of mattersolid (paramagnetic)
Melting point1000 K (1341 °F)
Boiling point2143 K (3398 °F)
Molar volume38.16 ×10-3 m3/mol
Heat of vaporization142 kJ/mol
Heat of fusion7.75 kJ/mol
Vapor pressure98 Pa at 371 K
Speed of sound1620 m/s
Electronegativity0.89(Pauling scale)
Specific heat capacity204 J/(kg*K)
Electrical conductivity3 106/m ohm
Thermal conductivity 18.4 W/(m*K)
1st ionization potential502.9 kJ/mol
2nd ionization potential965.2 kJ/mol
3rd ionization potential3600 kJ/mol
Most Stable Isotopes
isoNAhalf-life DMDE MeVDP
130Ba0.106%Ba is stable with 74 neutrons
132Ba0.101%Ba is stable with 76 neutrons
133Ba{syn.}10.51 yepsilon0.517133Cs
134Ba2.417%Ba is stable with 78 neutrons
135Ba6.592%Ba is stable with 79 neutrons
136Ba7.854%Ba is stable with 80 neutrons
137Ba11.23%Ba is stable with 81 neutrons
138Ba71.7%Ba is stable with 82 neutrons
SI units & STP are used except where noted.
Barium is a chemical element in the periodic table that has the symbol Ba and atomic number 56. A soft silvery metallic element, barium is an alkaline earth metal and melts at a very high temperature. Its oxide is called baryta[?] and it is primarily found in the mineral barite but is never found in its pure form due to its reactivity[?] with air. Compounds of this metal are used in small quantities in paints and in glassmaking.

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Notable Characteristics Barium is a metallic element that is chemically similar to calcium, yet is soft and in its pure form is silvery white resembling lead. This metal oxidizes very easily and when exposed to air and is highly reactive with water or alcohol. Barium is decomposed by water or alcohol. Some of the compounds of this element are remarkable for their high specific gravity, as its sulphate, called heavy spar. Applications Barium is primarily used in sparkplugs, vacuum tubes, fireworks, and in fluorescent lamps. Also:

History Barium (Greek "barys" meaning "heavy") was first identified in 1774 by Carl Scheele and extracted in 1808 by Sir Humphry Davy in England. The oxide was at first called barote, by Guyton de Morveau[?], which was changed by Antoine Lavoisier to baryta, which soon was modified to "barium" to describe the metal. Occurrence Because barium quickly becomes oxidized in air, it is difficult to obtain this metal in its pure form. It is primarily found in and extracted from the mineral barite which is crystalized barium sulphate.
Barium is commercially produced through the electrolysis of molten barium chloride[?] (BaCl2) Isolation (* follow):
(cathode) Ba2+* + 2e- ---> Ba (anode) Cl-* --> ½Cl2 (g) + e- Compounds The most important compounds are barium peroxide[?], chloride[?], sulfate[?], carbonate[?], nitrate[?], and chlorate[?]. When burned, barium salts glows green. (See "Uses" section above) Isotopes Naturally occurring barium is a mix of seven stable isotopes. There are twenty-two isotopes known, but most of these are highly radioactive and have half-lifes in the several millisecond to several minute range. The only notable exception is barium-133 which has a half-life of 10.51 years. Precautions All water or acid soluble barium compounds are extremely poisonous.
Oxidation occurs very easily and to remain pure, barium should be kept under a petroleum-based fluid (such as kerosene) or other suitable oxygen-free liquids that exclude air.

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Barium is also the latin name for the city Bari in Italy.

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