Di-μ-nitrato-bis­(μ-octa­ethyl pyro­phospho­ramide)­bis­[aqua­dinitratocalcium(II)]

The title compound, di-μ-nitrato-κ(3) O,O′:O;O:O,O′-bis­(μ-octa­ethyl pyro­phos­pho­ramide-κ(2) O:O′)bis­[aqua­bis­(nitrato-κ(2) O,O′)calcium(II)], [Ca(2)(NO(3))(4)(C(16)H(40)N(4)O(3)P(2))(2)(H(2)O)(2)] was obtained as a side product during the work up of the synthesis of octa­ethyl pyro­phospho­ramide and represents the first structurally characterized complex of this ligand. The compound crystallizes in the monoclinic space group P2(1)/n and the asymmetric unit contains one pyro­phospho­ramide mol­ecule and one Ca(2+) ion coordinated to two nitrate ions and one water mol­ecule. The complex exists as a dimer with a centre of inversion located between two eight-coordinate calcium(II) centres, which are bridged by two nitrate ions and two octa­ethyl pyro­phospho­ramide ligands. Each Ca(2+) cation is also coordinated to a further nitrate anion, acting as a bidentate ligand, and a water mol­ecule. The complexes stack parallel to the a axis and are held in place by a network of inter­molecular O—H⋯O hydrogen bonds also running parallel to a.