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Ba
Ba at. wt. 137.34
at. no. 56
m.p. 725°C
b.p. 1640°C
sp. gr. 3.5 (20°C)
valence 2.
| SHELL | K | L | M | N | O | P | Q |
| SUB SHELL | He | Neon | Argon | Krypton | Xenon | Radon | Eka-radon |
| 1s | 2s 2p | 3s 3p | 3d 4s 4p | 4d 5s 5p | 4f 5d 6s 6p | 5f 6d 7s 7p | |
| Barium | 1s22s22p63s23p63d104s24p64d105s25p6 | 4f05d06s2 | |||||
| Symbol | 1S0 | ||||||
Barium was discovered by Sir Humphry Davy in 1808. Before this, Baryta was distinguished from lime by Scheele in 1774. It is found only in combination with other elements chiefly in barite or heavy spar (sulfate) and witherite (carbonate) and is prepared by electrolysis of the chloride. Barium is a metallic element, soft, and when pure is silvery-white like lead; it belongs to the alkaline earth group, resembling calcium chemically. The metal oxidizes very easily and should be kept under petroleum or other suitable oxygen-free liquids to exclude air. It is decomposed by water or alcohol. The metal is used as a "getter" in vacuum tubes. The most important compounds are the peroxide (BaO2), chloride, sulfate, carbonate, nitrate and chlorate. Lithopone, a pigment containing barium sulfate and zinc sulfide, has good covering power, and does not darken in the presence of sulfides. The sulfate, as permanent white or blancfixe', is also used in paint, in x-ray diagnostic work, and in glassmaking. Barite is extensively used as a wetting agent in oil well drilling fluids, and also in making rubber. The carbonate is used as a rat poison, while the nitrate and chlorate give colors in pyrotechny. The impure sulfide phosphoresces after exposure to the light. The compounds and the metal are not expensive. Barium metal costs about $7 to $1 0/lb. All barium compounds that are water or acid soluble are poisonous. Naturaly occurring barium is a mixture of seven stable isotopes. Eighteen other radioactive isotopes are known to exist.
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