A layered aluminum phosphate, [C2N2H10][Al2(OH)2H2O(PO4)2]H2O, by the amine phosphate route

A layered aluminum phosphate, I, [C2N2H10][Al2(OH)2H2O(PO4)2]H2O, with Al:P ratio of 1:1 has been prepared using a novel synthetic route wherein the amine phosphate, [C2N2H10][HPO4], was reacted with Al3+ ions under hydrothermal conditions. I crystallizes in the triclinic space group P(−1) (No. 2); a=6.614(1), b=9.918(1), c=10.381(1) Å, α=115.3(1), β=90.2(1), γ=90.8(1)°; V=615.6(2) Å3; Z=2, D calc=2.029 gcm−3; μ (MoKα)=0.565 mm−1. The final R=0.07 and wR 2=0.17 and S=1.15 have been obtained for 198 parameters. The layered structure of I has Al both in trigonal bi-pyramidal and octahedral coordinations and the polyhedra are so connected as to give rise to 3-membered Al2P rings and infinite Al–O(H)–Al linkages. The structure is closely related to the mineral tancoite.