ABSTRACT
The asymmetric unit of the title compound, {[CaPd{CH3OHC(PO3)2}(H2O)5]·5/3H2O} n , consists of one half of the complex [Pd{CH3OHC(PO3)2}](2-) anion (point group symmetry m..), one Ca(2+) cation [site symmetry (.2.)] that is surrounded by three water mol-ecules (one of which is on the same rotation axis) and by three disordered lattice water mol-ecules. The anions form a trinuclear metallocycle around a crystallographic threefold rotation axis. The cations are related by a twofold rotation axis to form a [Ca2(H2O)10](2+) dimer. The slightly distorted square-planar coordination environment of the Pd(II) atoms in the complex anions is formed by O atoms of the bidentate chelating phospho-nate groups of the 1-hy-droxy-ethyl-idene-1,1-di-phospho-nate ligands. In the crystal, cations are bound to anions through -Ca-O-P-O- bonds, as well as through O-Hâ¯O hydrogen bonds, resulting in a three-dimensional polymer. The structure is completed by five disordered solvent mol-ecules localized in cavities within the framework.
