Lithium diaqua-nickel(II) catena-borodiphosphate(V) monohydrate.

The title borophosphate LiNi(H(2)O)(2)[BP(2)O(8)]·H(2)O was synthesized under hydro-thermal conditions. The crystal structure is isotypic with the Mg analogue and features helical [BP(2)O(8)](3-) borophosphate ribbons, constructed by BO(4) (2 symmetry) and PO(4) tetra-hedra. The borate groups share all their oxygen apices with adjacent phosphate tetra-hedra. The ribbons are connected via Ni(2+) cations that are located on twofold rotation axes. The cations have a slightly distorted octa-hedral oxygen coordination by four O atoms from the anion and by two water mol-ecules. The voids within the helices are occupied by Li(+) cations, likewise located on twofold rotation axes, in an irregular environment of five O atoms. The structure is stabilized by O-H⋯O hydrogen bonds between coordinated or uncoordinated water mol-ecules and O atoms that are part of the helices.