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'Crystal Structure' in keywords Facet   section ZfN Section A:Volume 049  [X]
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1994 (6)
1Author    Jacek ZaleskiRequires cookie*
 Title    Crystal Structure and Phase Transitions of [C(NH2)3]3Sb2C l9 * 0.9 H 20 A dam Pietraszko  
 Abstract    The room temperature structure of [C(NH2)3]3Sb2C l9 ■ 0.9 H 20 (GNCA) was solved. It crystal­ lizes in the monoclinic C2/c space group with a = 15.275, b = 8.794, c = 17.904 (in Ä), ß = 96.40°, V = 2390 Ä 3, Z = 4. Refinement of the atomic parameters by a least squares methods gave R = 0.042, wR = 0.039 for 1958 reflections with F>4ct(F). The structure consists of polyanionic (Sb2Cl|_)n layers built of deformed corner connected SbX^-octahedra. Two crystallographically inequivalent guanidinium cations are present, one situated between polyanionic layers, the other one together with a disordered water molecule inside cavities formed by polyanions. Temperature X-ray scattering experiments together with DSC studies were carried out above room temperature. Temperature dependence of the lattice parameters between 300 K and 380 K was determined and a phase transition of mixed order at 364 K was revealed. 
  Reference    Z. Naturforsch. 49a, 895—901 (1994); received June 7 1994 
  Published    1994 
  Keywords    Guanidinium, Chloroantimonate, Crystal structure, Phase transition, DSC 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-0895.pdf 
 Identifier    ZNA-1994-49a-0895 
 Volume    49 
2Author    Tsutomu Okuda, Yoshihiro Kinoshita, Hiromitsu Terao, Koji YamadaRequires cookie*
 Title    Structure and Bonding of Bromoantimonate (III) Complexes with Unusual Valency by Means of NQR and Powder X-Ray Diffraction  
 Abstract    NQR and powder X-ray diffraction were observed for several bromoantimonate (III) complexes which contain C"H2n+ jNF^ (n = 1 -3) or (C"H2lt + 1)2N H 2 (n = 1 -4) as a cation. The bond character, anion structure, crystal structure, and phase transition are discussed on the basis of the three-center-four-electron bond. A good correlation was found between the halogen NQR frequency and the Sb-X bond length. 
  Reference    Z. Naturforsch. 49a, 185—192 (1994); received July 23 1993 
  Published    1994 
  Keywords    81Br NQR, Temperature dependence, Phase transition, Crystal structure 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-0185.pdf 
 Identifier    ZNA-1994-49a-0185 
 Volume    49 
3Author    SundaraR. Am Aprabhu, EdwinA C Lucken, Gerald BernardinelliRequires cookie*
 Title    Crystal Structure and NQR of Two Copper (I) Complexes of 4,6-Dimethylpyrimidine-2-thione  
 Abstract    The crystal structure and 63Cu NQR spectra of two neutral hexanuclear Cu(I) complexes of 4,6-dimethylpyrimidine-2-thione, (Hdmpt); [dmptCu]6 6 CHCl3 (l) and [dmptCu]6 C2 H4 Cl2 (2), are reported. The number and relative intensities of the NQR resonances are in agreement with the results of the crystallographic study. The temperature-dependence of the resonances reveals that both compounds undergo a phase-change in the temperature range 77 K -3 0 0 K, both of which may be associated with the loss of a symmetry-element present in the high-temperature phase. The 3 5 C1 resonances of CHC13 in 1 could be observed in the low-temperature phase but the corresponding resonances for C2 H4 C12 in 2 were not detected. 
  Reference    Z. Naturforsch. 49a, 193—198 (1994); received August 30 1993 
  Published    1994 
  Keywords    6 3 Cu, 3 5 C1, Cu(I), Crystal structure 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-0193.pdf 
 Identifier    ZNA-1994-49a-0193 
 Volume    49 
4Author    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 
5Author    Hiroyuki Ishida, Yoshihiro Kubozono, Setsuo Kashino, Ryuichi IkedaRequires cookie*
 Title    Crystal Structure of Trimethylammonium Perchlorate in Three Solid Phases Including the Ionic Plastic Phase Obtainable above 480 K  
 Abstract    The crystal structures of (CH3)3NHC104 in three solid phases were studied by X-ray diffraction techniques. X-ray powder patterns taken at ca. 500 and 445 K revealed that the plastic phase (Phase I) attainable above 480 K crystallizes in a CsCl-type cubic structure with a = 5.845 (1) A, Z = 1, V = 199.7 (2) Ä3, and Dx = 1.327 gem -3, while Phase II, stable between 480 and 396 K, forms a tetragonal structure with a = 9.912 (4), c = 7.01 (2) Ä, Z = 4, V = 689 (3) A3, and Dx = 1.54 gem -3. The room temperature phase (Phase III) was studied by single crystal X-ray diffraction and found to form a monoclinic lattice with space group P2X , a = 5.749(1), b = 8.670(1), c = 7.5585 (9) A, ß = 102.66 (1)°, Z = 2, V = 367.6 (2) A , and Dx= 1.441 g em -3. Thermal measurements, differential thermal analysis and differential scanning calorimetry, were carried out on these solid phases, and the obtained results were compared with those observed for (CH3)3NHBF4. 
  Reference    Z. Naturforsch. 49a, 723—726 (1994); received March 12 1994 
  Published    1994 
  Keywords    Crystal structure, X-ray diffraction, Thermal measurements, Ionic plastic phase 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-0723.pdf 
 Identifier    ZNA-1994-49a-0723 
 Volume    49 
6Author    Hirom Itsu Terao, TsutomuO., Kichiro Koto, Shi-Qi, AlarichW. Eiss2Requires cookie*
 Title    81 Br NQR and Crystal Structure of Ethylammonium Tribromomercurate(II), CHgCHjNI-^HgBrg  
 Abstract    The 81Br NQR triplet spectrum of (CH3 CH2 NH)®(HgBr3)e was measured in the range 77 K to near the m.p. (99~106°C). decreases strongly with increasing temperature, exhibiting 136.784 MHz at 77 K and 128.129 MHz at 298 K. v2 decreases from 82.060 MHz at 77 K to 76.322 MHz at 298 K. v3 increases with temperature, showing v3 = 81.292 MHz at 77 K and 84.903 MHz at 298 K. Replacement of the ammonium hydrogens by deuterium produces a negative shift of Vj and positive ones of v2 and v3 at high temperatures. These shifts change with temperature from | — 0| up to |~ 2 0 0 | kHz. The crystal structure of the title compound was determined at room temperature: P 21/m, Z = 2, a = 1021.6(8) pm, b = 643.0(6) pm, c = 691.8(6) pm, ß = 96.96 (4)°. The coordination of the mercury atom by the bromines is trigonal bipyramidal; by formation of bridges Hg • • ■ Br • • ■ Hg by one of the three bromines (Br(2)) of the planar HgBr® ions a double chain of trigonal bipyramids is formed, running along the b-axis of the crystal. B r 1' and Br(3) are single bonded to Hg. The hydrogen bonds N -H • • • Br(1 and N -H • ■ • Br(' (twice), connect the H g-B r chains to planes lying parallel to the be plane at x = 0. The relations between the Br-NQR spectrum and the structure are discussed. 
  Reference    Z. Naturforsch. 49a, 202—208 (1994); received August 16 1993 
  Published    1994 
  Keywords    Mercury(II) Bromide Complex, Crystal Structure, 81Br NQR, * H -2D isotope effect, H-bonding 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-0202.pdf 
 Identifier    ZNA-1994-49a-0202 
 Volume    49