Solid state synthesis of binary metal chalcogenides

Abstract

Solid state reaction of metal halides MX_n (n = 1 or 2) with stoichiometric amounts of sodium chalcogenide (Na₂S₂ or Na₂E where E = S, Se or Te) at 300 °C for 48 h in evacuated ampoules affords a range of transition and main-group metal chalcogenides: ME₂ (M = Fe or Co, E = S or Te); M_(1 − x)E (M = Fe or Co, E = S); Ag₂E (E = S, Se or Te), Ni_(1 − x)E (E = S, Se or Te); NiS₂, MnS, FeSe, SnSe and SnTe along with co-formed salt. Washing of the highly sintered, fused product mixture with water resulted in isolation of crystalline binary chalcogenides, typically of a single phase in good yield (90%). The products were characterised by X-ray powder diffraction, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDXA) and i nfrared spectroscopy.