The orthorhombic polymorph of diammonium trichromate(VI) decaoxide, α-(NH4)2Cr3O10

Journal article, 2007

Synthesis and crystal structure of a trichromium(VI) decaoxide compound, α-(NH4)2Cr3O10, is reported. The crystal structure has been determined from three dimensional X-ray data collected at low temperature, 173 K. The structure is isomorphous with its Rb and Cs trichromate analogues, orthorhombic, space group Pbca, with a = 11.2558(3), b = 9.3193(3), c = 18.9819(5) Å and Z = 8. The title compound is composed of discrete [Cr3O10]2- chains held together by the counter ion charge and a hydrogen bonding network. The different conformations adopted by trichromate anion within its ammonium, alkali and organic salts are discussed.