Rhenium Pure Quadrupole Resonance Spectrum of Potassium Perrhenate

The rhenium pure quadrupole resonance spectrum of polycrystalline potassium perrhenate has been observed. The frequencies of both the ±52 ↔ ±32 and ±32 ↔ ±12 transitions for 185Re and 187Re were found and have the values 56.600, 28.312, 53.626, and 26.825 MHz, respectively, at room temperature. These values are compared with a “theoretical” value of the quadrupole coupling obtained by adding the calculated point-charge field-gradient tensor to that arising from the p character of the bonds, both based on an assumed electronic structure for the ReO4− ion. It is shown that a reasonable value of the polarization factor will provide agreement with experiment.