The 125Te Moessbauer absorption spectra of the thiourea, ethylenethiourea, and tetramethylthiourea derivatives of tellurium(II) and tellurium(IV)

The 125 Te Mössbauer spectra of a number of Te(II) and Te(IV) complexes of thiourea and related derivatives have been measured. The isomer shifts and quadrupole splittings for several of the compounds are interpreted in terms of a bonding scheme utilizing three-center, two-electron bonds in which the tellurium 5p orbitals participate. The 129 I Mössbauer spectrum of trans-TeEtu 2 129 I 2 is reported and the isomer shift and quadrupole splitting are shown to be consistent with the proposal that the iodine uses only a 5p orbital in bonding to the tellurium.