Synthesis and Characterization of Organically Templated Metal Arsenates with a Layer Structure: [NH3(CH2)3NH3]0.5[M(OH)AsO4] (M=Ga, Fe)

Two organically templated metal arsenates, [NH3(CH2)3NH3]0.5[M(OH)AsO4] (M=Ga, Fe), have been synthesized under hydrothermal conditions and characterized by single-crystal Xray diffraction and 71Ga NMR spectroscopy. The two compounds are isostructural and crystallize in the orthorhombic space group Fdd2 (No. 43) with a=9.5584(7) ?, b=41.593 (3) ?, c=5.6438(4) ?, V=2243.8(3) ?3, and Z=16 with R1=0.0302 for the Ga compound, and a=9.7301(2) ?, b=41.5035(2) ?, c=5.7411(1) ?, V=2318.45(8) ?3, and Z=16 with R1=0.0228 for the Fe compound. The structure consists of two-dimensional anionic sheets of metal arsenate in the ac plane with charge-compensating propanediammonium cations between the sheets. The sheets are constructed from infinite chains of cis-corner-sharing MO6 octahedra, which are joined by arsenate ligands. This work is one of the few studies concerning organically templated metal arsenates