Strontium Imidosulphonate, Sr₃N₂(SO₃)₄

By mixing together solutions of strontium chloride and normal sodium imidosulphonate the strontium sodium salt, SrNaNS₂O₆.3H₂O, is formed. The normal strontium salt can be obtained from this by dissolving in dilute hydrochloric acid, pouring at once into a slight excess of a warm concentrated solution of strontium hydroxide, and repeating twice to remove sodium. It forms thin glistening scales, and resembles the barium salt but is more soluble. The freshly dried salt contains 12 molecules of water, but after fourteen days' exposure only 5 molecules. By precipitating with a concentrated solution of the ammonium salt and evaporating in a desiccator, a hydrate containing 5 or 5½ molecules of water of crystallisation is formed. By boiling the duodecahydrate a slightly basic pentahydrate is obtained.

Crystalline acid and basic salts have also been prepared, and a mercurimidosulphonate, HgSr₂N₂(SO₃)₄.15H₂O.