Structure and stoichiometry of nanocrystalline silver sulfide

摘要

Powders of silver sulfide Ag2S with an average particle size from similar to 500 to similar to 20-40 nm have been synthesized by the chemical bath deposition. The powders with a particle size of similar to 500 nm have a monoclinic (space group P2(1)/c) acanthite structure (alpha-Ag2S) and the stoichiometric Ag2S composition. It has been revealed for the first time that silver sulfide nanopowders have the same monoclinic acanthite alpha-Ag2S structure but a nonstoichiometric composition similar to Ag1.93S and contain vacant sites in the metal sublattice. The change in the crystal structure upon the transition from cubic argentite beta-Ag2S to monoclinic acanthite alpha-Ag2S is considered.