Salt-flux synthesis of complex oxides: Cs0.33MoO3, CsFe(MoO4)2, and the inverse salt-inclusion phase Cs2Mo0.65O0.21Cl5.44

Recent work on the growth of complex oxides in salt fluxes is reviewed. Single crystals of Cs0.33MoO3, CsFe(MoO4)(2) and the new phase, Cs2Mo0.65O0.21Cl5.44, have been grown from the reaction of metal oxides Fe2O3, MoO3 and molybdenum powder in a eutectic CsCl/NaCl flux. Cs0.33MoO3 is one of the known molybdenum bronzes, featuring mixed valent molybdenum ions. CsFe(MoO4)(2) has a layered KAl(MoO4)(2) structure, which consists of infinite slabs of corner-sharing MoO4 and FeO6 polyhedra separated by layers of Cs+ cations. Cs2Mo0.65O0.21Cl5.44 forms with a new structure type (orthorhombic, Cmcm, a = 7.434(1)angstrom, b = 17.330(3)angstrom, c = 8.074(1)angstrom, Z = 4) which is comprised of isolated [Mo(O/Cl)Cl-5] octahedra embedded in a distorted CsCl matrix. Magnetic susceptibility measurements indicate antiferromagnetic ordering for both CsFe(MoO4)(2) (T-N = 4.5 K) and Cs2Mo0.65O0.21Cl5.44 (T-N = 7 K).