STRUCTURAL AND SPECTRAL STUDIES OF 2 MIXED ANIONIC (1 1) 3(II)[(TR-III/CR-III)(CN)(6)](2)CENTER-DOT-15H(2)O COMPLEXES (TR = CO, FE)/

The crystal structures of (1:1) Cd-3(II)[(Co-III/Cr-III)(CN)(6)](2). 1 5H(2)O(I) and Cd-3(II)[(Fe-III/Cr-III) (CN)(6)](2). 15H(2)O(II) have b een determined by the single-crystal diffraction method. These novel m ixed anionic systems crystallize in the cubic space group Fm (3) over bar m (No. 225) with a(0) = 10.650(2) and 10.898(2) Angstrom, respecti vely. The disordered structures contain 1 1/3 molecules in the unit ce ll. Full-matrix least-squares refinements of I and II yielded final re liability (R) factors of 0.027 (R-w = 0.034) and 0.036 (R-w = 0.045) w ith goodness-of-fit (GOF, Sigma(2)) values of 1.09 and 1.22 based on 1 46 and 124 unique reflections, respectively. All metal atoms are six-c oordinated octahedrally and the cationic divalent Cd atoms are linked to the (1:1) mixed metal atoms by cyanide bridging. A hydrogen-bonding network is set up within cavities of the crystal lattices (created by molecular disorder). Powder diffraction data are reported and evaluat ed according to quantitative figures-of-merit for I and II (M-20 = 140 .4 and 205.9, respectively). Thermal gravimetric analysis revealed 15 water molecules per formula unit in each complex, Conoscopic and infra red spectral results, as well as selected bond distances and angles, a re presented. (C) 1998 Academic Press.