Synthesis and characterisation of transition-metal-substituted gallium phosphates with the laumontite structure

Three novel metal-substituted gallium phosphates, (C3N2H5)(8)[Me8Ga16P24O96] (Me = Co, Fe, Mn), have been synthesised under solvothermal conditions and their structures determined using single-crystal X-ray diffraction. They are isostructural, with monoclinic symmetry, space group C 2/c and unit-cell dimensions ca. 15 x 13 x 15 Angstrom, beta ca. 111 degrees. The materials all have frameworks with the laumontite topology (structure type code LAU), constructed from alternating PO4 and MO4 tetrahedra (M = Me and Ga) with imidazole cations occupying sites within the channels of the framework. Magnetic susceptibility measurements show that the materials exhibit Curie-Weiss behaviour over wide ranges of temperature and that the transition metals are present as divalent cations. (C) Elsevier Science Inc. 1997.