The title compound, potassium nickel(II) digallium tris-(phosphate) dihydrate, K[NiGa(2)(PO(4))(3)(H(2)O)(2)], was synthesized hydro-thermally. The structure is constructed from distorted trans-NiO(4)(H(2)O)(2) octa-hedra linked through vertices and edges to GaO(5) trigonal bipyramids and PO(4) tetra-hedra, forming a three-dimensional framework of formula [NiGa(2)(PO(4))(3)(H(2)O)(2)](-). The K, Ni and one P atom lie on special positions (Wyckoff position 4e, site symmetry 2). There are two sets of channels within the framework, one running parallel to the [10] direction and the other parallel to [001]. These inter-sect, forming a three-dimensional pore network in which the water mol-ecules coordinated to the Ni atoms and the K(+) ions required to charge balance the framework reside. The K(+) ions lie in a highly distorted environment surrounded by ten O atoms, six of which are closer than 3.1Å. The coordinated water mol-ecules are within hydrogen-bonding distance to O atoms of bridging Ga-O-P groups.
