(NH₄)AgMoS₄: Synthesis, structure and catalytic activity

The synthesis, characterization and crystal structure of (NH ₄)AgMoS₄ is presented. (NH₄)AgMoS₄ was prepared by the stoichiometric reaction of AgNO₃ with (NH ₄)₂MoS₄. The black microcrystalline (NH ₄)AgMoS₄ is thermally unstable and contaminated by a phase that analyzes for Ag₂MoS₄. In the TGA continuous weight loss was observed corresponding to the loss of ammonia gas subsequent loss of sulfur and H₂S to give Ag₂S and MoS₂. In the infrared spectrum of (NH₄)AgMoS₄, characteristic bands for the ammonium ion at 1350-1400 cm^-1 and for the [MoS ₄]^2- group at 460 cm^-1 are observed. Crystals of (NH₄)AgMoS₄ were investigated using a synchroton source. (NH₄)AgMoS₄ is isostructural to (NH ₄)CuMoS₄ and crystallizes in the tetragonal space group I4 (Z = 2, a = 7.8740(3), c = 5.7733(4) Å). (NH₄)AgMoS ₄ can be used as a catalyst in the syngas conversion to higher alcohols with showing good activity and ethanol selectivity.