X-ray diffraction study of polymeric Mg complexes of clodronic acid

Two Mg complexes of (dichloromethylene)bisphosphonic acid disodium salt, [{Mg(H2O)6}{Mg(Cl2CP2O6)(H2O)}⋅7H2O]n (1) and [NaMg(Cl2CP2O6H)(H2O)5]n (2), were prepared and characterised by X-ray crystallography. The two compounds consist of similar one-dimensional magnesium clodronate chains; in 1, [Mg(H2O)6]2+ cations are located between the chains; and in 2, coordinated Na+ cations hold the chains together in a three-dimensional network. The packing of 1 resembles layers, with the chlorine atoms of clodronate pointing toward the interlayer section, which is filled with lattice water molecules; and a wide hydrogen network is formed in all three dimensions. The framework of 2 contains channels, surrounded by the Cl and O atoms of clodronate, and aqua ligands; the channels are occupied by water molecules.