Iodine compounds, isomer shift

Results obtained from the alkali iodides on the isomer shift, the NMR chemical shift and its pressure dependence, and dynamic quadrupole coupling are compared. These results are discussed in terms of shielding by the 5p electrons and of Lbwdins technique of symmetrical orthogonalization which takes into account the distortion of the free ion functions by overlap. The recoilless fractions for all the alkali iodides are approximately constant at 80°K. Recent results include hybridization effects inferred from the isomer shifts of the iodates and the periodates, magnetic and electric quadrupole hyperfine splittings, and results obtained from molecular iodine and other iodine compounds. The properties of the 57.6-k.e.v. transition of 1 and the 27.7-k.e.v. transition of 1 are compared. 

Relationship between Isomer Shift and Quadrupole Splitting in Some Iodine Compounds... 

Other Iodine Compounds. By studying the isomer shift and the quad-rupole hfs for a series of compounds, Perlow and Perlow (29) have calibrated the isomer shift scale which is independent of Equation 7. The number of p holes, hp, for the compounds of I2, KICI4 H2O, KIC12 H2O, and ICl has been inferred from the measured value of the quadrupole coupling constant, eqQ, and from the symmetry of the iodine lattice site. Since they found that the isomer shifts and hp are linearly related for these compounds, it appears that 5 electrons do not participate directly in the bonding, and the sp hybridization is negligible. Because of this linearity, they have been able to determine dh/dhp, which leads to a calibration of the isomer shift scale. 

Fig. 1S.J5 Chemical isomer shifts for the 1 resonance in some iodine compounds plotted against Te shifts in similar tellurium compounds. [Ref. 51, Fig. 5]...

Fig. 15.18 The chemical isomer shifts for and in a number of iodine compounds. The solid line is for ) / 8RJR ( I) = — 0-65. All data are...

Fig. 2.7. Isomer shifts for iodine(I) and tellurium(IV) compounds I-X, TeX " ArTeXj, and ArjTeXj (X = F, Cl, Br, I Ar = aryl). The isomer shifts are relative to ZnTe for the iodine compounds and to I/Cu for the tellurium compounds.

For tellurium, nuclear quadrupole resonance (NQR) data give an estimate of bond ionicities for TeX " (X = C1, Br, I) which, together with the datum for CaTe (assumed to contain the closed shell Te " ion), gave hi 25 = 0.45 mm/s (Cheyne, Johnston Jones, 1972). The same value was obtained from the observed linear relationship for the isomer shift of isoelect ronic compounds of iodine and tellurium. An approximate value for 125 of 2.7 mm/s may be obtained from the same ratio (Parish, 1982h). 

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