OXIMIDOSULPHOXATES OR öULPHAZOTATES. QÇ) 



then nearly all dissolved by adding^ dilute hydrochloric acid with 

 continual stirring- until a solution is obtained neutral or only slightly 

 alkaline to litmus. The turbid solution is as quickly as possible 

 filtered, by vacuum-pump, into excess of warm baryta-water. The 

 precipitate thus obtained when washed with boiled-out water, hot or 

 cold, is the norm;d barium salt free from alkali and from carbonate. 

 It is a voluminous curdy precipitate at first, but generally changes to 

 a denser powder, crystalline under the microscope but to the naked 

 eye chalk-like when dry. It is practically insoluble in water, but 

 soluble in ammonium chloride. It is fully decomposed in the cold by 

 ammonium or sodium carbonate solution. Heated dry, it suddenly 

 decomposes into barium sulphate and gases. It loses water at com- 

 mon temperatures in dry air, and nearly all at 110°. Its composition, 

 calculated and found, is shown by the following table, in which A 

 refers to one pre[)aration with 4 Aq., and 1] to another with 8 Aq. : — 



l>arium 



.Sulphur 14-83 14-80 13-69 13-46 



Tivo-thirds normal barium oximidosidphonalcs, BaHNSoO^, can be 

 obtained in solution by adding just enough acid to the normal barium 

 salt. When the normal salt is free from alkali and the acid is 

 sulphuric the solution filtered is pure. When the normal barium salt 

 is combined with any potassium or sodium salt the solution obtained 

 by means of an acid is treated as described fnv getting the pure normal 

 salt, which is then aijain converted to the two-thirds normal salt bv 

 sulphuric acid. The solution of this salt is distinctly acid to litmus 

 and hydrolyses too readily to admit apparently of crystallising out the 

 salt from it. 



