Disodium calcium dinickel(II) bis-[diphosphate(V)] deca-hydrate.

In the title compound, Na(2)CaNi(2)(P(2)O(7))(2)(H(2)O)(10), there are two distinct P-atom sites, each tetra-hedrally coordinated by four O atoms. The resulting phosphate tetra-hedra link through a common O atom, forming a [P(2)O(7)](4-) diphosphate unit. The Ni-O coordination is square pyramidal with four O atoms from two diphosphate groups in equatorial positions and the vertex occupied by a water O atom.