Organometallic reagents are being examined for the low-temperature preparation of metal sulfide powders which are desired as precursors to 8-12 µm infrared-transmitting optical ceramics. The most studied system is the reaction of diethylzinc with hydrogen sulfide in toluene solution at or near room temperature. Electron microscopy and X-ray powder diffraction data show that the white ZnS product consists of 0.1 μm agglomerates with crystallite sizes of ~50 Å. The product is predominantly β-ZnS (cubic structure), which contains residual hydrocarbon due to unreacted zinc alkyl groups (determined by acid hydrolysis and gas chromatography). In order to optimize the reaction, several experimental parameters have been varied including the nature of the alkyl group on zinc, the method of addition of reagents, temperature, solvent, and concentration of reactants. The reaction has also been extended to organometallic complexes of Al and Mg and also to a mixed system of Zn and Al.
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