Mössbauer Effect of 129I in Pyridine Complexes of Iodine Monohalides

The values of isomer shift and quadrupole interaction at the ¹²⁹I nucleus in IBr and ICl complexes with cyclic nitrogen bases have been measured. These have been used to estimate $\sigma$ and $\pi$ bondings in these complexes. All these complexes exhibit a linear N–I–X (X≡Cl, Br) linkage. Although the bromine complexes show a systematic dependence of the isomer shift on the basicity of the complexing cyclic amines, no such trend is observed in chlorine complexes.