Synthesis and Properties of α- and β-Modifications of Bis(1-Hydroxyethane-1,1-Diphosphonato(1-))Diaquocopper(II) Trihydrate: Crystal Structure of β-[Cu{CH3COH(PO3H2)(PO3H)}2(H2O)2] • 3H2O

Two modifications [alpha(I) and beta(II)] of the [Cu(H(3)L)(2)(H(2)O)(2)] center dot 3H(2)O compound were synthesized, and [Cu(H(3)L)(2)] (III) was prepared by the dehydration of II at 130 degrees C. Compounds I-III were characterized by X-ray powder diffraction and thermal analyses. Crystals II were subjected to X-ray structural study. The Cu atom has a distorted tetragonal-bipyramidal coordination (4 + 2) because to four O atoms of the two bidentate-chelate H(3)L(-) ligands lying in the equatorial plane (Cu-O 1.948 and 1.970 angstrom) and the two O atoms of the H(2)O molecules occupying axial positions (Cu-O 2.456 angstrom).