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'Hydrogen Bond' in keywords Facet   Publication Year 1994  [X]
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1Author    Masao Hashimoto, Shuji Matsumoto, Masakazu Kunitomo, Haruo Niki, Hirotaka Odahara, Katsuji TamakiRequires cookie*
 Title    35C1 NQR Relaxation and Hydrogen Bond in Some Chloral Hemiacetals  
 Abstract    The crystal structure of chloral ethylhemiacetal has been determined at 291 K: monoclinic, space group C f -P 2 lt Z = 2, a = 854.5(1), b = 594.0(3), c = 853.3(1) pm, ß = 108.30(2)°, R = 0.0962. A sharp decrease of the spin lattice relaxation time 7i found for the 35C1 N Q R o f the CC13 groups in chloral methyl-, ethyl-and n-heptylhemiacetals is attributed to the onset of reorientation of the group over a potential barrier o f ca. 39, 37, and 32 kJ/m ol, respectively. An unusual vs. 1/T curve with a 7i minimum superimposed on the sharp decrease of 7\ due to the reorientation was observed for each of the three Cl N Q R lines of nH p-C H . This phenom enon is tentatively ascribed to a fluctuation of EFG caused by jum ping m otion o f the hydrogen atom s in the OH groups. 
  Reference    Z. Naturforsch. 49a, 279 (1994); received August 16 1993 
  Published    1994 
  Keywords    Crystal structure, Hydrogen bond, Chlorine N Q R, Spin lattice relaxation 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-0279.pdf 
 Identifier    ZNA-1994-49a-0279 
 Volume    49 
2Author    H. Arald Hillebrecht, G.Erhard Thiele, Alrik Koppenhöfer, Heinrich VahrenkampRequires cookie*
 Title    Kristallstruktur und Schwingungsspektren von Zn(NH 3)4(C104)2 Crystal Structure and Vibrational Spectra of Zn(N H 3)4(C104)2  
 Abstract    The title compound Z n (N H 3)4(C104)2 crystallizes in the space group F 43m with a = 10.240(1) A. The crystal structure consists of tetrahedral Z n (N H 3)4 cations and two non­ equivalent C 104 anions with crystallographic Td symmetry. The complex ions constitute an arrangement which is known from the Zintl phase M gAgAs. The Z n(N H 3)4 cations are ccp packed with perchlorate anions in octahedral and tetrahedral voids. W hereas the C 104 ions centered at tetrahedral holes do not interact with the other lattice components, the perchlo­ rate ions in the octahedral voids are connected with the ammine ligands by a hydrogen bonded three-dimensional network involving all their N, H, and O atoms. The repeating unit of this network is a N40 4(m-H)12 cube with N -H = 1.19(2)A and O -H = 1.98(2)A . Raman and IR spectra were recorded between 150 and 4000 cm -1. A ll the expected internal m odes of the com plex ions could be detected and assigned. The crystallographically different C 104 anions have nearly the same vibrational spectra, only a slight splitting o f two IR m odes is observed. 
  Reference    Z. Naturforsch. 49b, 1163—1168 (1994); eingegangen am 25. März 1994 
  Published    1994 
  Keywords    Zinc Am m ine, Perchlorate, Cubic Structure, Hydrogen Bonds, Vibrational Spectra 
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 TEI-XML for    default:Reihe_B/49/ZNB-1994-49b-1163.pdf 
 Identifier    ZNB-1994-49b-1163 
 Volume    49 
3Author    Hendrik Möller, Ellen Suchanek, HeinzDieter Lutz, Werner PaulusRequires cookie*
 Title    Neutronenbeugungs-Untersuchung von M g(I03)2*4H 20 -Einkristallen Neutron Diffraction Studies on M g (I0 3 )2 -4H 20 Single Crystals  
 Abstract    The crystal structure of M g (I 0 3)2-4 H 20 has been determined by neutron single crystal diffraction (P2j/c, Z = 2, R = 2,2% on the basis of 1107 observed reflections). M g (I 0 3)2-4 H 20 forms a layered structure built up of octahedral M g(H 20) 4(I 0 3)2 units linked by hydrogen bonds. The two crystallographically different water m olecules are in­ volved in asymmetric, nearly linear hydrogen bonds to adjacent iodate ions (vOD of matrix isolated HDO: 2480, 2475, 2425 und 2412 cm -1, IR spectroscopic data, 90 K). The strength of the hydrogen bonds as well as that of other iodate hydrates is discussed in terms o f both the synergetic effect and Brown's bond valences. 
  Reference    Z. Naturforsch. 49b, 1334—1338 (1994); eingegangen am 2. Mai 1994 
  Published    1994 
  Keywords    Magnesium Iodate Tetrahydrate, Crystal Structure, Neutron Diffraction Studies, Hydrogen Bonds 
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 TEI-XML for    default:Reihe_B/49/ZNB-1994-49b-1334.pdf 
 Identifier    ZNB-1994-49b-1334 
 Volume    49