Morphology of Zinc Sulfide Particles Produced from Various Zinc Salts by Homogeneous Precipitation

Colloidal sols of ZnS were prepared by thermal decomposition of thioacetamide in acidic zinc solutions. Precipitation was carried out in the presence of nitrate, acetate, chloride, and sulfate ions. Particle morphology was influenced by the chemical nature of the anions present in the solution as well as the rate of sulfide ion generation. Spherical, monodisperse particles having a specific type of particle size distribution, i.e., monosized, bimodal, or continuous distribution, with mean sizes in the range of 0.15 to 3 μm, were formed depending on the anion type and sulfide ion generation rate. Individual particles always consisted of clusters of sphalerite crystallites except when sulfide ions were generated at low rates and sulfate ions were present. In such cases a mixture of α- and β-ZnS was formed.