SYNTHESIS AND CHARACTERIZATION OF TRANSITION-METAL-SUBSTITUTED GALLIUM PHOSPHATES WITH THE LAUMONTITE STRUCTURE

Three novel metal-substituted gallium phosphates, (C3N2H5)(8)[Me8Ga16P 24O96] (Me = Co, Fe, Mn), have been synthesised under solvothermal con ditions and their structures determined using single-crystal X-ray dif fraction. They are isostructural, with monoclinic symmetry, space grou p C 2/c and unit-cell dimensions ca. 15 x 13 x 15 Angstrom, beta ca. 1 11 degrees. The materials all have frameworks with the laumontite topo logy (structure type code LAU), constructed from alternating PO4 and M O4 tetrahedra (M = Me and Ga) with imidazole cations occupying sites w ithin the channels of the framework. Magnetic susceptibility measureme nts show that the materials exhibit Curie-Weiss behaviour over wide ra nges of temperature and that the transition metals are present as diva lent cations. (C) Elsevier Science Inc. 1997.