Vibrational Raman spectra of liquid and solid ethylene

1970 ◽  
Vol 48 (5) ◽  
pp. 513-520 ◽  
Author(s):  
S. M. Blumenfeld ◽  
S. Paddi Reddy ◽  
H. L. Welsh
Keyword(s):  
Crystal Structure ◽  
Raman Spectrum ◽  
Force Constant ◽  
Raman Spectra ◽  
Short Range ◽  
Short Range Order ◽  
Freezing Point ◽  
Low Frequency ◽  
Intermolecular Force ◽  
Linear Dispersion

The Raman spectra of liquid and solid C2H4 have been examined at a reciprocal linear dispersion of 8 cm−1/mm. The liquid spectrum presents some evidence of short-range order in the liquid near the freezing point. The gerade fundamentals and low-frequency librational modes have been observed in the Raman spectrum of the solid. Analysis of the observed splitting in terms of H-atom repulsion indicates that the intermolecular force constant is 950 dyn/cm, and the crystal structure is P21/n1. The origin of other observed structures is uncertain.

The crystal structure of orlovite, KLi2 Ti(Si4 O10)(OF): the first example of the short-range order of Ti in true trioctahedral micas

2018 ◽  
Vol 30 (2) ◽  
pp. 399-402
Author(s):  
Elena Sokolova ◽  
Frank C. Hawthorne ◽  
Atali A. Agakhanov ◽  
Leonid A. Pautov ◽  
Vladimir Yu. Karpenko
Keyword(s):  
Crystal Structure ◽  
Short Range ◽  
Short Range Order ◽  
Range Order

Diffuse scattering and short-range order in uranium iodine phthalocyanine [U1−x Pc2]I2−y and the X-ray structure analysis of crystals with diffuse superstructure reflections

2003 ◽  
Vol 59 (3) ◽  
pp. 384-392 ◽  
Author(s):  
J. Krawczyk ◽  
A. Pietraszko ◽  
R. Kubiak ◽  
K. Łukaszewicz
Keyword(s):  
Crystal Structure ◽  
Structure Analysis ◽  
Diffuse Scattering ◽  
Short Range ◽  
Short Range Order ◽  
Crystal Structure Analysis ◽  
Range Order ◽  
Small Range ◽  
X Ray ◽  
Unit Cells

Crystals of uranium iodine phthalocyanine present an example of a disordered commensurate modulated structure of the intergrowth type. The short-range order of both uranium ions and iodine chains [I_3^-] n has been analysed by Reverse Monte Carlo (RMC) simulation of X-ray diffuse scattering. The diffraction pattern of uranium iodine phthalocyanine contains diffuse superstructure reflections. In the routine crystal structure analysis diffuse superstructure reflections may be either omitted or measured and classified along with other Bragg reflections. The crystal structure of uranium iodine phthalocyanine is an example of such ambiguity. The crystal structures of two specimens of [U1−x Pc2]I2−y with slightly different composition have been published in the literature with different space groups and unit cells. We have shown that the structure of both specimens differs only in the degree of short-range order and is isostructural with [YbPc2]I2. We have also shown that while the omission of diffuse reflections results in the average crystal structure, the treatment of these reflections as normal Bragg reflections is incorrect and produces the structure averaged over a limited small range.

Crystal Structure of Cu2Gd2/3S2: Interlayer Short-Range Order of Gd Vacancies

2000 ◽  
Vol 152 (2) ◽  
pp. 332-339 ◽  
Author(s):  
Mitsuko Onoda ◽  
Xue-an Chen ◽  
Akira Sato ◽  
Hiroaki Wada
Keyword(s):  
Crystal Structure ◽  
Short Range ◽  
Short Range Order ◽  
Range Order

scholarly journals Isotope Shifts in Ammonium Perrhenate

1986 ◽  
Vol 41 (1-2) ◽  
pp. 335-337 ◽  
Author(s):  
T. L. Haslett ◽  
R. J. C. Brown ◽  
Y. S. Park ◽  
H. F. Shurvell
Keyword(s):  
Raman Spectrum ◽  
Raman Spectra ◽  
Short Range ◽  
High Accuracy ◽  
Lattice Parameters ◽  
Ammonium Ion ◽  
Isotopic Substitution ◽  
Isotope Shifts ◽  
Ammonium Perrhenate ◽  
Lattice Modes

Isotope shifts in the NQR and Raman spectra o f ammonium perrhenate due to 15H and 2H substitution are reported. The effect of isotopic substitution at the nitrogen on the NQR spectrum is zero; in the Raman spectrum the translational lattice modes of the ammonium ion are clearly differentiated from the torsional modes. The effect of deuteration on the NQR frequency has been measured to high accuracy and confirms that to a moderately good approximation the effect of deuteration is equivalent to the application of pressure. The effect of deuteration on the lattice parameters has been measured. NQR spectra of slightly deuterated ammonium perrhenate show a shoulder with a characteristic shift due to short range influence of NH3D+.

Gem amphiboles from Mogok, Myanmar: crystal-structure refinement, infrared spectroscopy and short-range order–disorder in gem pargasite and fluoro-pargasite

2018 ◽  
Vol 83 (03) ◽  
pp. 361-371 ◽  
Author(s):  
Maxwell C. Day ◽  
Frank C. Hawthorne ◽  
Umberto Susta ◽  
Giancarlo Della Ventura ◽  
George E. Harlow
Keyword(s):  
Crystal Structure ◽  
Fine Structure ◽  
Infrared Spectroscopy ◽  
Infrared Spectra ◽  
Short Range ◽  
Short Range Order ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Structure Refinement ◽  
Crystal Structure Refinement

AbstractThe crystal structures of six gem-quality pargasites and fluoro-pargasites from Mogok, Myanmar, space group C2/m, Z = 2, have been refined to R1 indices of 2.20–2.90% using MoKα X-radiation. The unit formulae were calculated from the results of electron-microprobe analysis, and were used with the refined site-scattering values and the observed mean bond lengths to assign site populations. TAl occurs at both the T(1) and T(2) sites but is strongly ordered at T(1). [6]Al is partly disordered over the M(2) and M(3) sites but does not occur at the M(1) site. ANa is split between the A(2) and A(m) sites and K occurs at the A(m) site. The infrared spectra in the principal OH-stretching region were measured and the fine structure was fit to component bands. The component bands were assigned to short-range ion arrangements over the configuration symbol M(1)M(1)M(3)–O(3)–A–O(3):T(1)T(1) using the refined site-populations and the expected frequencies from previously assigned spectra in more simple amphibole compositions, and correspond to the local arrangements: (1) MgMgMg–OH–Na–OH:SiAl; (2) MgMgMg–OH–Na–F:SiAl; (3) MgMgAl–OH–Na–OH:SiAl and (4) MgMgAl–OH–Na–F:SiAl.

scholarly journals Crystal Structure of Cobalt Oxide Superconductors and Their Short-Range-Order Stacking

2011 ◽  
Vol 53 (6) ◽  
pp. 409-415
Author(s):  
Mitsuko ONODA ◽  
Kazunori TAKADA ◽  
Takayoshi SASAKI
Keyword(s):  
Crystal Structure ◽  
Cobalt Oxide ◽  
Short Range ◽  
Short Range Order ◽  
Range Order ◽  
Oxide Superconductors

The crystal structure of orlovite, KLi2Ti(Si4O10)(OF): the first example of the short-range order of Ti in true trioctahedral micas

2018 ◽  
Vol 30 (2) ◽  
pp. 399-402 ◽  
Author(s):  
Elena Sokolova ◽  
Frank C. Hawthorne ◽  
Atali A. Agakhanov ◽  
Leonid A. Pautov ◽  
Vladimir Yu. Karpenko
Keyword(s):  
Crystal Structure ◽  
Short Range ◽  
Short Range Order ◽  
Range Order

The Crystal Structure of Polylithionite-1M from Darai-Pioz, Tajikistan: the Role of Short-range Order in Driving Symmetry Reduction in 1M Li-rich Mica

2019 ◽  
Vol 57 (4) ◽  
pp. 519-528 ◽  
Author(s):  
Frank C. Hawthorne ◽  
Elena Sokolova ◽  
Atali A. Agakhanov ◽  
Leonid A. Pautov ◽  
Vladimir Yu. Karpenko
Keyword(s):  
Crystal Structure ◽  
Long Range ◽  
Short Range ◽  
Short Range Order ◽  
Bond Valence ◽  
Range Order ◽  
Sum Rule ◽  
Space Group ◽  
Bond Valence Sum

Abstract The crystal structure of polylithionite-1M from Darai-Pioz, (K0.97Na0.03Rb0.01)Σ1.01(Li2.04Al0.84 Ti4+0.09Fe3+0.03)Σ3.00(Si3.98Al0.02)O10[F1.68(OH)0.33]Σ2, a 5.1974(4), b 8.9753(6), c 10.0556(7) Å, β 100.454(1)°, V 461.30(6) Å3, space group C2, Z = 2, was refined to R1 = 1.99% using MoKα X-radiation. In the space group C2, there are three octahedrally coordinated M sites in the 1M mica structure: the M(1) site is occupied by Li+ and minor vacancy that is likely locally associated with Ti4+ at the M(2) site; the M(2) site is occupied dominantly by Al3+, with other minor divalent to tetravalent cations; the M(3) site is completely occupied by Li+. In the space group C2, the structure is completely ordered. Each non-bridging O2– ion is surrounded by an ordered arrangement of 2Li+ + Al3+ + Si4+ with an incident bond-valence sum of 1.95 vu (valence units). The F– ion is coordinated by Li+ + Li+ + Al3+ with an incident bond-valence sum of 0.84 vu (values around F– generally tend to be lower than ideal). Thus, the valence-sum rule is satisfied, both long range and short range. In the space group C2/m, there is long-range order but not short-range order. There are three different short-range arrangements, one of which has bond-valence deficiencies of 0.38 and 0.49 vu around the non-bridging O2– ion and the F– ion, destabilizing the structure relative to the more ordered arrangement of the C2 structure, which conforms more closely to the valence-sum rule. The drive to lower the symmetry in polylithionite-1M from C2/m to C2 comes from the short-range bond-valence requirements of the structure.

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