Inorganic Chemistry, Vol.40, No.27, 6940-6947, 2001
Liquid ammonia mediated metathesis: Synthesis of binary metal chalcogenides and pnictides
Addition of stoichiometric amounts of low valent metal halides to liquid ammonia solutions of disodium chalcogenide (Na2E; E = S, Se, Te) afforded a range of both crystalline (PbE (E = S, Se, Te), TIE (E = S, Se), Tl5Te3, Ag2E (E = S, Se, Te)) and X-ray amorphous (MS (M = Ni, Cu, Zn, Cd, Hg), M2E3 (M = Ga, Im E = S, Se, Te), HgE (E = Se, Te), CuE (E = S, Se, Te), Cu2S) metal chalcogenides in good yield (95%). Reactions between metal halides and sodium pnictides (Na(3)Pn; Pn = As, Sb) in liquid ammonia also afforded X-ray amorphous material (M(3)Pn(2), M = Zn, Cd; MPn, M = Fe, Co, Ni) in good yield (95%). Isolation of the metal chalcogenides and pnctides was achieved through washing with CS2 and distilled water, All reactions were complete within 36 h. Products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDXA), electron probe analysis, FT-IR spectroscopy, Raman spectroscopy, microanalysis, and band gap measurements. Annealing amorphous material at 250-300 degreesC for 48 h induced sufficient crystallinity for analysis by X-ray powder diffraction.