6533b839fe1ef96bd12a6e38

RESEARCH PRODUCT

Crystal structure and mössbauer spectroscopy studies of the ferrimagnetic complex bimetallic salt hexaamminechromium (III) hexachloroferrate (III), [Cr(NH3)6][FeCl6]

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description

The crystal and molecular structures of the ferrimagnetic bimetallic complex salt hexaamminechromium(III) hexachloroferrate(III), [Cr(NH3)6][FeCl6], have been determined from single-crystal, three-dimensional x-ray diffraction counter data. The compound crystallizes as orange coloured crystals in the space groupC2/c of the monoclinic system with Z=4 and has cell dimensionsa=11.325(1) A,b=11.387(1) A,c=11.233(1) A, and β=90.83(1)A. The structure was refined by using segmented block diagonal least-squares techniques to discrepancy indices R and Rw of 0.0233 and 0.0285, respectively. The metal ions occupy sites with symmetry $$\bar 1$$ and are nearly octahedrally coordinated. In the [FeCl6]3− anion there are three independent Fe−Cl distances with a mean of 2.393(2) A, and the maximum angular deviation from octahedral geometry is 1.20. In the [Cr(NH3)6]3+ cation, the mean of the three independent Cr−N distances is 2.079 (7) A, and the maximum angular deviation from octahedral geometry is 0.70. The structural data provide an explanation for the observed quadrupole splitting of 0.214 mms−1 as seen in the Mossbauer spectrum at 292.6 K and reveal superexchange pathwaysvia close amine proton-chloride anion contacts with lead to 3D-ferrimagnetic ordering near 2.8 K.