14N nuclear quadrupole resonance in K4Mo(CN)8 · 2H2O and K4W(CN)8 · 2H2O

The 14N nuclear quadrupole resonance spectra of K4Mo(CN)8 · 2H2O and isostructural K4W(CN)8 · 2H2O between 77 and 293°K were studied. The difference in the charge distribution of the cyanides in a dodecahedral ion predicted by group theory was found to be small and to fall within the variation produced by the crystal field of physically inequivalent sites. The lack of matching between lines from similar sites in these isostructural compounds was attributed to the variations in the cyanide charge distribution produced by differences in the orbital overlap as a result of the relativistic effects present in the W atom. Also differences were found between the temperature dependence of the spectra of two of the six inequivalent N sites.