Preparation and Properties of Cobalt Sulfide, Nickel Sulfide, and Iron Sulfide

Co 9 S 8, Ni 3 S 2, and Fe 7 S 8 were prepared as single-phase polycrystalline materials by heating the appropriate metal sulfates in a controlled mixture of H 2 and H 2 S at low temperature. The products were characterized by x-ray diffraction, thermogravimetric analysis, and magnetic susceptibility measurement. The x-ray diffraction pattern and field dependent magnetic susceptibility of Fe 7 S 8 were affected by the thermal history of the sample. The observed differences can be related to the vacancy ordering associated with ferrimagnetic Fe 7 S 8 .