Layered cobalt phosphate grafted with hydrazinium ligands : Co 2 ( PO 4 ) ( H 2 PO 4 ) N 2 H 5

The title compound has been hydrothermally synthesized from elemental cobalt, phosphoric acid, and hydrazine, and characterized by single crystal X-ray diffraction [crystal data: triclinic, P1Å, a~5.1393(6), b~6.363(1), c~11.293(1) AÊ , a~95.65(1), b~96.874(9), c~92.79(1)3], IR, TGA, and magnetic measurement. The structure is made of neutral layers of corner-sharing PO4 tetrahedra and dimers of edge-sharing 5and 6coordinate cobalt polyhedra. The hydrazinium cations, N2H5 , are coordinated as ligands on both sides of the layers and complete the octahedral coordination of the six-coordinate cobalt. The so-grafted layers are held together by strong and extensive hydrogen bonding. Thermally the compound is stable up to 360 3C, above which it decomposes in a single step to yield cobalt pyrophosphate. Magnetic measurements show paramagnetic Curie±Weiss behavior over the temperature range 5±300 K.