NQR investigation of intercalates and complexes of cadmium and lead iodides with pyridine, aniline, and piperidine

127I and 14N NQR have been investigated in two cadmium idodide - pyridine compounds, the intercalate CdI2+5.9 pyridine and the CdI2Py2 complex. In the intercalate, iodine is mainly ionic and nitrogen like in pure pyridine; in the complex, iodine exhibits 30% covalency while nitrogen, coordinated to the central cadmium atom of the complex, and presents coupling constants e2Qq and η smaller than in pure pyridine. The difference between the two compounds is also revealed by the thermal coefficient of the quadrupole coupling constants and the relaxation. Results on the other title compounds are also given.