Nuclear Quadrupole Coupling Constants and the Ionic Character of Covalent Bonds

1966 ◽  
Vol 44 (10) ◽  
pp. 4036-4038 ◽  
Author(s):  
William J. Considine
Keyword(s):  
Coupling Constants ◽  
Ionic Character ◽  
Covalent Bonds ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole

Aspects of hybridization

1950 ◽  
Vol 202 (1071) ◽  
pp. 548-564 ◽  
Keyword(s):  
Dipole Moments ◽  
Atomic Orbital ◽  
Second Order ◽  
Coupling Constants ◽  
Covalent Bonds ◽  
Orbital Hybridization ◽  
Quadrupole Coupling ◽  
Orbital Approximation ◽  
Nuclear Quadrupole ◽  
Oxygen Atoms

It has been shown that the pairing theory of orbital hybridization accounts satisfactorily for the variations which are observed in the properties of C-H bonds. Since heteropolar effects are in the opposite directions to the effects described, it is concluded that hybridization influences the properties of predominantly covalent bonds to a greater extent than do differences in electronegativity. The extent of second-order hybridization in the molecules CH, NH and OH has been dealt with in the light of this analysis. The consequences of the electronegativity concept have been examined on the basis of a generalized atomic orbital approximation. In particular, variations of the electronegativity of the carbon, nitrogen and oxygen atoms in different states of hybridization have been analyzed. The idea of 'lone' electrons has been formalized and the results of this definition have been discussed. Finally, the effects of orbital hybridization on the dipole moments and nuclear quadrupole coupling constants of molecules have been considered.

scholarly journals Correlation of NQR and Chemical Bond Parameters

1990 ◽  
Vol 45 (3-4) ◽  
pp. 195-212 ◽  
Author(s):  
Alarich Weiss ◽  
Silvia Wigand
Keyword(s):  
Spectroscopic Method ◽  
Vibrational Frequencies ◽  
Coupling Constants ◽  
Ionic Character ◽  
Charge Density Distribution ◽  
Quadrupole Coupling ◽  
Quadrupole Resonance ◽  
Cross Correlations ◽  
Nuclear Quadrupole ◽  
Nqr Parameters

Abstract Nuclear quadrupole resonance is an effective spectroscopic method to investigate the charge density distribution in solids. The range of compounds which may be investigated is wide, reaching from a crystal lattice built up by an ordered arrangement of neutral molecules in the crystalline material to ionic crystals and to metallic solids. First the correlations between NQR quantities and bond parameters which become apparent from the molecular orbital picture will be discussed, e.g. Hammett a, x-parameter, ionic character i, s-character, ionicity, electronegativity in their connection to NQR. Then, the correlations of NQR frequencies, respectively nuclear quadrupole coupling constants, with bond lengths and bond angles are considered. Cross correlations, e.g. of NQR frequencies with bond distances, bond distances with vibrational frequencies, and vibrational frequencies with NQR frequencies are discussed as are pK A dependencies of NQR parameters. The connection of e

19F Nuclear Quadrupole Coupling in some Halomethanes

1986 ◽  
Vol 41 (1-2) ◽  
pp. 171-174 ◽  
Author(s):  
M. Frank ◽  
F. Gubitz ◽  
W. Ittner ◽  
W. Kreische ◽  
A. Labahn ◽  
...  
Keyword(s):  
Angular Distribution ◽  
Simple Model ◽  
Temperature Dependence ◽  
Coupling Constants ◽  
Temperature Dependent ◽  
Distribution Method ◽  
Quadrupole Coupling ◽  
Time Differential ◽  
Nuclear Quadrupole

The 19F quadrupole coupling constants in CF4, CHF3, CClF3 and CHClF2 are reported. The measurements were carried out temperature dependent using the time differential perturbed angular distribution method (TDPAD). The temperature dependence can be satisfactorily described in the framework of the Bayer-Kushida theory. A simple model is used to explain the appearance of H-F and Cl-F coupling constants in CHF3/CHClF2 and CClF3, respectively.

33S Nuclear Hyperfine Structure in the Rotational Spectrum of Thiazole

1993 ◽  
Vol 48 (12) ◽  
pp. 1219-1222 ◽  
Author(s):  
U. Kretschmer ◽  
H. Dreizler
Keyword(s):  
Fourier Transform ◽  
Hyperfine Structure ◽  
Molecular Beam ◽  
Microwave Spectroscopy ◽  
Coupling Constants ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
Centrifugal Distortion Constants

Abstract We investigated the 33S nuclear quadrupole coupling of thiazole- 33S in natural abundance by molecular beam Fourier transform microwave spectroscopy. In addition the 14N nuclear quadrupole coupling could be analyzed with high precision. We derived the rotational constants A = 8529.29268 (70) MHz, B = 5427.47098 MHz, and C = 3315.21676 (26) MHz, quartic centrifugal distortion constants and the quadrupole coupling constants of 33S χaa = 7.1708 (61) MHz and χbb= -26.1749 (69) MHz and of 14N χ aa = -2.7411 (61) MHz and χbb = 0.0767 (69) MHz.

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