The above compound of titanium sesquisulphate and sulphuric acid may be alternatively described as titanosulphuric acid; the alkali salts of this acid will then be complex rather than double salts. By combination with rubidium and ammonium sulphates the following titanosulphates have been obtained by Stahler: 3Ti2(SO4)3.Rb2SO4.24H2O; 3Ti2(SO4)3.(NH4)2SO4.18H2O. In addition to these a sodium salt of the composition Ti2(SO4)3.Na2SO4.5H2O has been obtained in violet crystals by the electrolytic reduction of sodium titanic sulphate solution. It is prepared technically and used as a reducing agent. Perchlorates can be reduced and estimated by its means.
Besides these salts titanium sesquisulphate forms alums, which, like other alums, diminish in solubility with increase in electropositiveness of the alkali metal. The rubidium and caesium salts, Rb2SO4.Ti2(SO4)3.24H2O and Cs2SO4.Ti2(SO4)3.24H2O have been prepared by Piccini. |