Showing papers by "Allan Zalkin published in 1964"
TL;DR: The crystal structure of CaWO4 (scheelite) has been refined with single-crystal x-ray diffraction data as discussed by the authors, and the crystal structure has been shown to be stable with respect to the number of cells in the tetragonal cell a=5.243±0.002, c=11.376± 0.003 A.
Abstract: The crystal structure of CaWO4 (scheelite) has been refined with single‐crystal x‐ray diffraction data. For the tetragonal cell a=5.243±0.002, c=11.376±0.003 A. Oxygen coordinates 0.1504, 0.0085, and 0.2111 correspond to Ca–O distances 2.44 and 2.48 A and W–O distances 1.78 A.
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TL;DR: In this article, the atomic parameters were refined by least squares, X-ray counter data being used for 2576 independent reflections, the positions of the hydrogen atoms found by least square and by Fourier methods confirm the assignment of hydrogen bonds made previously for the isomorphous CoSO4.
Abstract: The atomic parameters were refined by least squares, X-ray counter data being used for 2576 independent reflections. The positions of the hydrogen atoms found by least squares and by Fourier methods confirm the assignment of hydrogen bonds made previously for the isomorphous CoSO4.6H20. Average interatomic distances are: water coordinated to Mg, Mg-O = 2-06 A; hydrogen bonds, 0 -0=2 .82 A; sulfate ion, S-O=1.473 /~ (uncorrected), 1.486 ~ (corrected for thermal motion).
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TL;DR: The crystal structure of ferrichrome A (C41H58N9O20Fe�4H2O) has been determined by x-ray diffraction and the absolute configuration of the three hydroxamate rings at the iron atom is that of a left-handed propeller.
Abstract: The crystal structure of ferrichrome A (C41H58N9O20Fe·4H2O) has been determined by x-ray diffraction. The amino acid sequence in the hexapeptide ring is confirmed to be -Orn-Orn-Orn-Ser-Ser-Gly-, and the conformation of this ring is trans at each peptide linkage. The absolute configuration of the three hydroxamate rings at the iron atom is that of a left-handed propeller. Disorder is found concerning the positions of some of the side chains and one of the four water molecules.
26 citations
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TL;DR: Zalkin, Allan; Forrester, J.D., Templeton, David; Williamson, Stanley M; Koch, Charles W. H; and Forster, David.
Abstract: Author(s): Zalkin, Allan; Forrester, J.D.; Templeton, David. H.; Williamson, Stanley M.; Koch, Charles W.