Preparation and characterization of a hexagonal ammonium tungsten bronze phase (NH4)xWO3

Abstract

The decomposition of ammonium paratungstate 5(NH4)2O.12WO3.5H2O in hydrogen has been studied thermogravimetrically and the formation of a hexagonal ammonium tungsten bronze phase, (NH4)xWO3(x∼0.25) established. Powder X-ray diffractometer studies, and measurements of electrical conductivity, magnetic susceptibility and reflectance spectra show that this phase is both iso-structural and iso-electronic with corresponding tungsten bronzes formed by potassium and rubidium.