Cerium(IV) fluoride and fluoride-arsenate frameworks

摘要

Five new cerium (IV) fluoride and fluoride-arsenate framework structures have been synthesised hydrothermally using CeF_4 as a fluoride source. Cs[Ce_2F_8[F·H_2O]] (I) consists of layers, formed from linked Ce(F,O)_n polyhedra cross-linked by hydrogen bonding that defines large channels containing the caesium ions. [(NH_4)_5(H_2O)_2][Ce_ 4(AsO_4)_6(H_2O)F_3] (II), has an open framework structure with large channels filled with NH_ 4~ + cations and H_2O molecules. Ce[AsO_ 4]F (III) and Ce[AsO_4]F[H_2O] (IV) exhibit two types of bridging (Ce-O-Ce and Ce-F-Ce) bonds between Ce(O,F)_n polyhedra, and (NH_4)[CeF_2(AsO_4)] (V), is isostructural with the previously reported fluoride-phosphate (NH_ 4)[Ce~(IV)F_2(PO_4)] (R. B. Yu, D. Wang, T. Takei, N. Kumada, H. Koizumi and N. Kinomura, J. Solid State Chem., 2001, 157, 180).1