Crystal growth, structure, and properties of KLa(CrO4)2
Abstract
The crystal growth and structure of KLa(CrO4)2, its spectroscopic properties, and thermal decomposition are reported. Crystals of KLa(CrO4)2 were obtained from an aqueous solution of K2Cr2O7+ La2O3(3:1), maintained at 150 °C for 1 month: space group P21/c, Z= 4, with a= 8.729(2), b= 7.4752(7), c= 11.049(6)Å, and β= 92.42(1)°. They consist of parallel layers of [La(CrO4)2]nn– perpendicular to the a axis, the K+ being situated between these layers. Of the possible 36 absorption bands, 16 were observed in the i.r. and Raman spectra, which were analysed using factor-group analysis. The thermal decomposition proceeds in one step at 720–760°C according to KLa(CrO4)2→ LaCrO3+ KCrO2+O2.