Preparation and Properties of Ammonium Hexachlorozirconate(IV) and Its Reaction with Gaseous Ammonia

Abstract Ammonium hexachlorozirconate (NH4)2ZrCl6 was prepared by the direct reaction of ZrCl4 with NH4Cl. The X-ray powder diffraction and the density measurements showed that it has a face-centered cubic lattice with a=10.127(2) Å and is isostructural with K2PtCl6. The hexachlorozirconate undergoes ammonolysis in gaseous ammonia at room temperature, forming ZrCl3(NH2)·xNH3 and NH4Cl. The ammonolysis product reverts to the initial (NH4)2ZrCl6 on heating to 250 °C in the ammonia atmosphere. The hexachlorozirconate vaporizes at about 450 °C. The reaction of ZrCl4 with gaseous ammonia was also studied in comparison with that of the hexachlorozirconate.