International Tables for X-ray Crystallography. Errata

Abstract

An X-ray diffraction data set consisting of 1772 unique reflections (27118 measured) has been collected on Cs3CoC15 at 295 K. The unit cell is tetragonal, I4/mcm, with a = 9.2315 (15), c = 14.5535 (24) A, Z = 4. A free-atom form factor, harmonic model does not fit the data well. From the low-angle low-intensity data JR(F) = 0.022, Rw(I) = 0.030 for 54 unique reflec-tions] charges of +1.27 + 0.10 e on the cobalt and-0.82 + 0.12 e on the tetrachlorocobaltate-anion C1 atoms are obtained. The cobalt possesses a 3d population of 7.1 + 0.1 e and a much more diffuse charge of 0.6 + 0.16 e. Comparison with neutron diffraction, polarized neutron diffraction and spectroscopic results suggests that the highest-angle data may be substantially affected by anharmonicity. 'Anharmonicity' parameters are derived.