Crystallography at 0.3 A: Single-crystal study of Cr(NH3)6Cr(CN)6 at the Cornell High-Energy Synchrotron Source

Short-wavelength (λ=0.302 A) synchrotron radiation at CHESS has been used to analyze the crystal and electronic structure of hexaamminechromium(III) hexacyanochromate(III), Cr(NH3)6Cr(CN)6, using a total of 7224 intensity measurements. Special attention is given to corrections for counter deadtime, beam-polarization effects and second-order contamination of the beam. An unequal stepsize method is introduced to improve sampling of the extremely narrow diffraction peaks. Structural and experimental data are: Ranti 3, a=b=c=7.4635 (7) A, α=β=γ=97.830 (10)0, V=419.3 A3, Z=1, R=0.0285 for 1968 independent reflections and 44 parameters. Deformation density maps show bond and lone-pair features and contain remarkably little noise in regions away from the atoms. The study shows that excellent quality data can be obtained with synchrotron radiation, in particular when small crystal size is combined with short wavelengths. (orig.)