Hydrothermal Synthesis and Characterization of Two Mixed Valence Piperazine-Vanadium Phosphates: (C4H12N2)(H3O)[(VOPO4)4(H2O)H2PO4]· 3H2O and (C4H12N2)[(VO)(VO2)2(H2O)(PO4)2]

A new iron phosphate, [C2N2H10]2[Fe5F4(PO4)(HPO4)6], containing F- ions as part of the framework, has been synthesized hydrothermally using iron acetylacetonate as the source for iron and ethylenediamine (en) as the amine. A network of [Fe(O/F)6] octahedra and PO4 tetrahedra, linked through their vertices, forms the three-dimensional architecture with onedimensional channels bound by 8-T atom (T=Fe, P), wherein the disordered en molecules are located. The connectivity between the Fe centers via Fe-O/F-Fe linkage giving rise to a pentamer unit is worthy of note. Crystal data: tetragonal, space GROUP =P43212, a=9.864(1), c=30.353(1) ?, V=2953.1(1) ?3, Z=4, R1=0.025, wR2=0.066.