Transition-metal Dion-Jacobson layered perovskites, M0.5LaNb2O7

Transition-metal layered perovskites were synthesized by topotactic methods. Compounds of the approximate formula M0.5LaNb2O7 (M = Fe, Ni) were obtained directly by ion exchange between RbLaNb2O7 and MBr2 at low temperature (350 °C). Cu0.5LaNb2O7 was synthesized by another route where CuCl2 was topochemically deintercalated from (CuCl)LaNb2O7 at 550 °C under a dynamic vacuum. The series M0.5LaNb2O7 (M = Fe, Ni, Cu) is isostructural with adjacent double-perovskite layers aligned, as in RbLaNb2O7. The set of compounds all exhibit Curie–Weiss paramagnetism.