Temperature dependence of the 35Cl nuclear quadrupole resonance frequencies of the trimeric and tetrameric phosphonitrilic chlorides

1967 ◽  
Vol 45 (14) ◽  
pp. 1669-1676 ◽  
Author(s):  
M. Kaplansky ◽  
M. A. Whitehead
Keyword(s):  
Temperature Dependence ◽  
Nuclear Quadrupole Resonance ◽  
Unit Cell ◽  
Crystallographic Data ◽  
Chlorine Atoms ◽  
Resonance Frequencies ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole ◽  
35Cl Nuclear Quadrupole Resonance

The 35Cl nuclear quadrupole resonance frequencies of the trimeric and tetrameric phosphonitrilic chlorides have been studied as a function of temperature. Two forms of the tetramer were used and the differences in their spectra ascribed to crystallographic effects. Correlation of each of the lines in the trimer to a set of chlorine atoms in the unit cell were attempted using crystallographic data.

35Cl and 37Cl Pure Quadrupole Resonance in α-CH2ClCOOH: Hydrogen Bonding and Chlorine Isotope Effect

1978 ◽  
Vol 33 (1) ◽  
pp. 74-77 ◽  
Author(s):  
Helmut Rager
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Temperature Dependence ◽  
Bond Length ◽  
Nuclear Quadrupole Resonance ◽  
Isotope Effect ◽  
Unit Cell ◽  
Chlorine Atoms ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

The temperature dependence of the pure nuclear quadrupole resonance of 35Cl and 37Cl in solid α-CH2ClCOOH has been measured from 77 K to 298 K. The NQR spectrum consists of a doublet arising from the two nonequivalent chlorine atoms in the unit cell. The temperature dependence was calculated using the Bayer-Kushida theory which gives a satisfactory fit to the NQR spectra in the temperature range investigated. From the NQR data evidence of an isotope effect was found for both nonequivalent chlorine atoms. The isotope effect depends on the C-Cl bond length and its direction probably on the state of binding of the chlorine atoms. The NQR results and their interpretation are consistent with the crystal structure of α- CH2ClCOOH.

Nuclear Quadrupole Resonance Studies of Chelated Antimony Complexes. Part III. The Carboxylates: RCO2SbCl4

1986 ◽  
Vol 41 (1-2) ◽  
pp. 179-185
Author(s):  
Claudine Gerard-Dion ◽  
Joyce Rupp-Bensadon ◽  
Edwin A. C. Lucken
Keyword(s):  
Phase Change ◽  
Nuclear Quadrupole Resonance ◽  
Chlorine Atoms ◽  
Resonance Frequencies ◽  
Quadrupole Resonance ◽  
Antimony Complexes ◽  
Quantitative Basis ◽  
Nuclear Quadrupole ◽  
The Difference

The 35Cl, 121Sb and 123Sb resonance frequencies for seventeen tetrachloro(carboxylato)antimony V compounds, RCO2SbCl4, are reported. The results confirm the difference in the effects of the substituent on the equatorial chlorine atoms and the axial chlorine atoms of the SbCl4 group, previously remarked in Parts I and II of this series, and this effect has been put on a more quantitative basis by correlating the observed frequencies with the pK’s of the corresponding acids.The compounds with R = isopropyl and R = cyclopropyl both show a phase change in the region of 140 K which may correspond to reorientation of the substituent about the R - CO2 axis.

An arsenic-75 nuclear quadrupole resonance study of α and β As4S3

1972 ◽  
Vol 25 (11) ◽  
pp. 2291 ◽  
Author(s):  
TJ Bastow ◽  
ID Campbell ◽  
HJ Whitfield
Keyword(s):  
Thermal Expansion ◽  
Temperature Dependence ◽  
Nuclear Quadrupole Resonance ◽  
Electrostatic Field ◽  
Β Phase ◽  
Field Gradients ◽  
Α Phase ◽  
Resonance Frequencies ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

The nuclear quadrupole resonance frequencies of 75As in the α and β forms of As4S3 have been measured at 77, 195, and 293 K. The frequencies at 77 K were: α phase 64.87 65.94 79.56 MHz β phase 65.42 67.16 79.65 MHz An analysis is presented in terms of Townes-Dailey theory and of the temperature dependence in terms of Bayer-Brown theory. The differences in frequencies of the α and β forms were attributed to the effect of electrostatic field gradients, estimated by lattice sums. Allowance must be made for the thermal expansion of the lattice to obtain a consistent interpretation.

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