Synthesis and structural characterization of mixed transition metal derivatives of malefic acid:: (M0.52+Fe0.52+)(C4H3O4)-2•4H2O (with M2+=Mn, Co, Ni, and Zn) using powder diffraction data

Four mixed metal derivatives of maleic acid with general formula, (M-0.5(2+), Fe-0.5(2+))(C4H3O4)(-)(2)center dot 4H(2)O (M2+=Mn, Co, Ni, and Zn) were prepared by slow evaporation at room temperature of the aqueous solutions containing the metal carbonates and maleic acid. The X-ray powder diffraction data of the prepared materials, collected with a SIEMENS D5005 diffractometer, showed that they are isostructural and crystallize in a triclinic unit cell similar to the cell of the parent single cation maleates. The unit cell volume of the synthesized mixed metal derivatives varies linearly between that of the Ni complex (V=319.15(8) angstrom(3): a=5.213(1) angstrom, b=7.349(2) angstrom, c=9.194(2) angstrom, alpha=108.77(2)degrees, beta=104.65(3)degrees, gamma=93.11(2)degrees) and that of the Mn-derivative (V=327.8(1) angstrom(3): a=5.296(2) angstrom, b=7.371(2) angstrom, c=9.326(4) angstrom, alpha=109.59(3)degrees, beta=104.70(2)degrees, gamma=93.35(3)degrees). Rietveld refinements confirmed the isostructural nature of this family of compounds.