Copper(II) malonate trihydrate: Crystal structure of monoclinic form

The crystal structure of the monoclinic form of copper malonate trihydrate is determined by X-ray diffraction analysis (C2/c, a = 21.1219 Angstrom, b = 21.1144 Angstrom, c = 14.0149 A, beta = 116,005 degrees). The copper atom s occupy 5 crystallographically independent positions in the independent pa rt of the unit cell. The residues of malonic acid act as bidentate chelate and tridentate chelate bridging ligands forming the complex [Cu(Mal)(2)(H2O )(2)](2-) anion and associates of two types: neutral {[Cu(H2O)(4)][Cu(Mal)( 2)(H2O)(2)]} and positively charged {[Cu(H2O)(4)][Cu(Mal)(2)(H2O)][Cu(H2O)( 4)]}(2+). The structural units are joined into the framework by the system of hydrogen bonds. The obtained data are compared to the known orthorhombic form of this compound (Pbcn, a = 14.861 Angstrom, b = 14.989 Angstrom, c = 12.645 Angstrom).