Calcium, barium and strontium; the most stable acidic hydroxides are those of the elements placed in groups VB, VIB and Viib of the periodic table.
The acid is considered to possess the structure 0 2 S(SH) (OH), since sodium thiosulphate reacts with ethyl bromide to give sodium ethyl thiosulphate, which on treatment with barium chloride gives presumably barium ethyl thiosulphate.
BARYTES, a widely distributed mineral composed of barium sulphate (BaSO 4).
The free acid is obtained (in dilute aqueous solution) by the addition of dilute sulphuric acid to an aqueous solution of the barium salt.
This acid is also formed by decomposing barium or lead permanganate with dilute sulphuric acid.
Soc., 1900, 77, p. 648) prepares pure hydrobromic acid by covering bromine, which is contained in a large flask, with a layer of water, and passing sulphur dioxide into the water above the surface of the bromine, until the whole is of a pale yellow colour; the resulting solution is then distilled in a slow current of air and finally purified by distillation over barium bromide.
Barium sulphate, BaSO 4, is the most abundant of the naturally occurring barium compounds (see Barytes) and can be obtained artificially by the addition of sulphuric acid or any soluble sulphate to a solution of a soluble barium salt, when it is precipitated as an amorphous white powder of specific gravity 4.5.
Percarbonates.-Barium percarbonate, BaCO 4, is obtained by passing an excess of carbon dioxide into water containing barium peroxide in suspension; it is fairly stable, and yields hydrogen peroxide when treated with acids (E.
This salt, on standing, decomposes into barium dithionate, BaS206, and diethyl disulphide, (C2H5)2S2, which points to the presence of the SH group in the molecule.
The free acid forms dark red deliquescent crystals and is obtained by decomposing the silver salt with hydrochloric acid, or the barium salt with dilute sulphuric acid.