Ni3Te2O2(PO4)2(OH)4, an open-framework structure isotypic with Co3Te2O2(PO4)2(OH)4

Single crystals of Ni-3(TeO(OH)(2))(2)(PO4)(2), trinickel(II) bis[(oxidodihydoxidotellurate(IV)] bis(phosphate),were obtained by hydrothermal synthesis at 483 K, starting from NiCO3 center dot 2Ni(OH)(2), TeO2 and H3PO4 in a molar ratio of 1:2:2. The crystal structure of Ni3Te2O2(PO4)(2)(OH)(4) is isotypic with that of Co3Te2O2(PO4)(2)(OH)(4) [Zimmermann et al. (2011). J. Solid State Chem. 184, 3080-3084]. The asymmetric unit comprises two Ni (site symmetries 1, 2/m) one Te (m), one P (m), five O (three m, two 1) and one H (1) sites. The tellurium(IV) atom shows a coordination number of five, with the corresponding [TeO3(OH)(2)] polyhedron having a distorted square-pyramidal shape. The two NiII atoms are both octahedrally coordinated but form different structural elements: one constitutes chains made up from edge-sharing [NiO6] octahedra extending parallel to [010], and the other isolated [NiO2(OH)(4)] octahedra. The two kinds of nickel/oxygen octahedra are connected by the [TeO3(OH)(2)] pyramids and the [PO4] tetrahedra through edge- and corner-sharing into a three-dimensional framework structure with channels extending parallel to [010]. Hydrogen bonds of medium strength between the hydroxy groups and one of the phosphate O atoms consolidate the packing. A quantitative structure comparison between Ni3Te2O2(PO4)(2)(OH)(4) and Co3Te2O2(PO4)(2)(OH)(4) is made.