Nickel Sulphite, NiSO3, may be prepared in two stages of hydration. The hexahydrate, NiSO3.6H2O, crystallises in tetrahedra on evaporating a solution of monoxide in aqueous sulphurous acid in the cold over sulphuric acid. If, on the other hand, the solution is concentrated on the water-bath, the tetrahydrate, NiSO3.4H2O, separates out as a green crystalline mass.
The salt readily oxidises in solution. It dissolves in ammonia, yielding a blue crystalline hydrated triammoniate, NiSO3.3H2O.3NH3. A basic sulphite is obtained by addition of sodium sulphite to a solution of a nickel salt, and warming. With ammonium sulphite a green, crystalline precipitate of Nickel Ammonium Sulphite, (NH4)2SO3.3NiSO3.18H2O, is obtained. |