Complex Uranyl Sulphites

By the addition of potassium bisulphite to a solution of uranyl sulphite in excess of aqueous sulphurous acid, a yellowish-green precipitate of composition K₂O.2UO₃.3SO₂ is obtained. If the uranyl sulphite is treated with a limited quantity of sulphurous acid, golden-yellow crystals separate, which, according to Kohlschiitter, may be formulated 4UO₃.4SO₂.11H₂O, whilst the potassium uranyl salt when treated in the same way yields the compound K₂O.4UO₃.5SO₂. This, on treatment with water, yields uranyl sulphite and the complex sulphite K₂O.3UO₃.2SO₂. The latter compound may also be obtained as fine, deep yellow, crystalline needles by treating a solution of uranyl nitrate with an excess of a neutral solution of potassium sulphite.

Corresponding sodium and ammonium salts of the above complexes have been prepared.

Ammonium and potassium salts of composition R₂O.UO₃.2SO₂ have also been described.

A basic uranyl sulphite, 5(UO₂)₂SO₃.UO₂(OH)₂.10H₂O, has been described, but that this is a definite compound may be questioned.