Formation of Cadmium Sulphide - Manganese(2)Sulphide Solid Solutions by Coprecipitation from Aqueous Solutions of Corresponding Sulphate by Ammonium Sulphide

Abstract

When a 0.27 M aqueous solution of (NH4)2S, in a quantity 10 molO/o short of the stoichiometric value, is added to an aqeuous solution of CdS04 and MnS04 of various compositions, with 8042- being 0.3 M, a continuous CdS : MnS solid solution is not formed: saturation is reached for at most about 0.1 molO/o MnS, the corresponding relative concentration of MnS04 being 4 molO/o. With increasing this concentration to 20 mol O/o, MnS begins to precipitate in substantial amounts, reaching 19.8 molO/o for MnS04 equal to 50 molO/o. Debye-Scherrer diagrams show that the precipitates are quasi amorphous, composed essentially of cubic CdS with certain quantities of hexagonal CdS and MnS. This makes it impossible to distinguish, by these diagrams only, mechanical mixtures from solid solutions