Computer Simulations of Thermal Expansion in Lanthanum-Based Perovskites

The nitridophosphates Rb3P6N11 and Cs3P6N11 were synthesized by the reaction of the respective alkali azides with P3N5 at 35 kbar and 1300°C using a multianvil assembly. The products were obtained as colorless crystalline powders. According to powder diffractometry it was obvious that Rb3P6N11 and Cs3P6N11 are isotypic to K3P6N11. The crystal structures were refined from powder diffraction data by the Rietveld method using the atomic coordinates of K3P6N11 as starting values (Rb3P6N11, P4132, Z=4, a=1049.74(1) pm; Cs3P6N11, a=1065.15(1) pm).