Chemical accuracy and precision in Rietveld analysis: The crystal structure of cobalt(II) acetate tetrahydrate

Journal Article · Sat Mar 01 04:00:00 EST 1997 · Powder Diffraction

DOI:https://doi.org/10.1017/S0885715600009404· OSTI ID:475693

Kaduk, J A; Partenheimer, W ^[1]

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1. Amoco Corporation, P.O. Box 3011, MC F-9, Naperville, Illinois 60566 (United States)

The crystal structure of cobalt(II) acetate tetrahydrate, Co(C{sub 2}H{sub 3}O{sub 2}){center_dot}4H{sub 2}O, has been refined using single-crystal, laboratory powder, and synchrotron powder diffraction data, both individually and in various combinations. The compound crystallizes in the monoclinic space group P2{sub 1}/c, with a=4.80688(3), b=11.92012(7), c=8.45992(5) {Angstrom}, {beta}=94.3416(4){degree} at 27{degree}C, and Z=2. The crystal structure consists of discrete centrosymmetric {ital trans}-Co(C{sub 2}H{sub 3}O{sub 2})(H{sub 2}O){sub 4} complexes, linked by a three-dimensional network of hydrogen bonds. Each complex participates in 14 hydrogen bonds, 12 intermolecular, and 2 intramolecular. Compared to the single-crystal refinement, refinement of laboratory powder data yielded an average difference in bond distances of 0.02 {Angstrom}, in bond angles of 3{degree}, and in root mean square atomic displacements of 0.07 {Angstrom}. The standard uncertainties of the bond distances were 0.01 {Angstrom}, compared to the 0.001{endash}0.002 {Angstrom} in the single-crystal refinement. Refinement of the synchrotron powder data yielded improved accuracy and precision. It proved impossible to locate or refine hydrogen positions using a single-powder dataset, but the hydrogens could be refined using rigid groups in a joint refinement of the two powder datasets. Even from powder refinements, it is possible to obtain suitable accuracy and precision to distinguish C{endash}O and C=O bonds, and to examine details of chemical bonding. {copyright} {ital 1997 International Center for Diffraction Data.}

• Sponsoring Organization: USDOE
• DOE Contract Number: FG02-86ER45231
• OSTI ID: 475693
• Journal Information: Powder Diffraction, Journal Name: Powder Diffraction Journal Issue: 1 Vol. 12; ISSN 0885-7156; ISSN PODIE2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACETATES
BOND ANGLE
BOND LENGTHS
COBALT COMPOUNDS
CRYSTAL STRUCTURE
ORGANOMETALLIC COMPOUNDS
SPACE GROUPS
SYNCHROTRON RADIATION
X-RAY DIFFRACTION