Barium

Barium (sym. Ba, eq. 137) is the metal present in heavy spar (sulphate of baryta) and baryta. It was regarded as a white metal, until the researches of Dr Matthiessen demonstrated that it possesses a yellow colour. As yet, the metal barium has not been obtained in mass, but only as a powder. It decomposes water readily at ordinary temperatures, and exposed to the air, quickly combines with oxygen, forming the oxide of barium, BaO, or Baryta (a.v.), an earth resembling ordinary caustic lime. The sulphide of barium, BaS, is obtained when the sulphate of baryta, $\backslash text\{BaSO\}\_4$, in powder is mixed with finely pulverised coal, and the whole being placed in a crucible, is raised to a red-heat in a furnace. The result is, that 4 atoms of the carbon, C, of the coal carry off the 4 atoms of oxygen in the sulphate of baryta as carbonic oxide, CO, whilst the barium united solely with sulphur is left behind as the sulphide of barium, BaS. The chloride of barium is prepared by adding hydrochloric acid, HCl, to a solution of the sulphide of barium, BaS, when sulphuretted hydrogen, $\backslash text\{H\}\_2\backslash text\{S\}$, escapes, and chloride of barium remains behind, and on evaporation of the liquid, is obtained in crystals. Barium is employed in making Oxygen (q.v.).