Date Published: May 01, 2010
Publisher: International Union of Crystallography
Author(s): Abderrazzak Assani, Mohamed Saadi, Lahcen El Ammari.
In an attempt to hydrothermally synthesize a phase with composition Co2Cu(PO4)2·H2O, we obtained the title compound, Co2.39Cu0.61(PO4)2·H2O instead. Chemical analysis confirmed the presence of copper in the crystal. The crystal structure of the title compound can be described as a three- dimensional network constructed from the stacking of two types of layers extending parallel to (010). These layers are made up from more or less deformed polyhedra: CoO6 octahedra, (Cu/Co)O5 square pyramids and PO4 tetrahedra. The first layer is formed by pairs of edge-sharing (Cu/Co)O5 square pyramids linked via a common edge of each end of the (Cu/Co)2O8 dimer to PO4 tetrahedra. The second layer is undulating and is built up from edge-sharing CoO6 octahedra. The linkage between the two layers is accomplished by PO4 tetrahedra. The presence of water molecules in the CoO4(H2O)2 octahedron also contributes to the cohesion of the layers through O—H⋯O hydrogen bonding.
For the properties of and background to metal phosphates, see: Clearfield (1988 ▶); Gao & Gao (2005 ▶); Viter & Nagornyi (2009 ▶); Harrison et al. (1995 ▶). For compounds with the same structure, see: Anderson et al. (1976 ▶); Liao et al. (1995 ▶); Sørensen et al. (2004 ▶); Moore & Araki (1975 ▶).