The ¹²⁵Te Mössbauer Absorption Spectra of the Thiourea, Ethylenethiourea, and Tetramethylthiourea Derivatives of Tellurium(II) and Tellurium(IV)

Abstract

The lZ5Te Mossbauer spectra of a number of Te(ll) and Te(1V) 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 L291 Mossbauer spectrum of ~r a t~s -T e E t u~"~I~ 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.

125Te Mössbauer spectra of the polyatomic cations of tellurium

“…Finally, TeO, precipitated out and the somewhat smaller isomer shift for this compound is consistent with that generally found for Te(1V) oxides and oxyanions in the solid state, reflecting some stereochemical activity of the 5s electrons (10).…”

“…The prepared absorbers had a thickness of 5-10 mg cm-l of lZ5Te. The general procedures used in recording the Mossbauer spectra have been reported elsewhere (10). The spectra were computer fitted to Lorentzians using a program described in ref.…”

A Mössbauer study of organotellurium compounds. Part II. Halides, acetates, and benzoates

“…L\ hile the coupling constant for PhjSb is 530 MHz (10). Taking the ratio of the principal components of the field gradient tensor per 5p electron for antinionq and tellurium to be 0.87 (21), the ratio of the coupling constants corresponds to a ratio of Qg,,ci(lrlSb) Qe,(lZ5Te) of 1.7, which is not inconsistent with previous estimates of the magnitude of the quadrupole moments of these t u o states (10,22). Thus the magnitudes of the q~~aclrupole splitting for Ph2(CH3)TeI and Ph(CH3)?TeI are consistent with those compounds containing pyramidal Ph2(CH3)Te+ and Ph(CH3)?Tet cations which are iso-electronic and iso-structural ~i t h Ph3Sb.…”

X-ray photoemission studies of tellurium and some of its compounds

“…5 times greater and of opposite sign than that caused by the removal of a 5p electron. The cause of the discrepancy in magnitude between these two results can be attributed to the following factors: (1) The assumption that only 5p electrons take part in chemical bonding in thiourea and its derivative compounds of tellurium may not be totally valid. For example, in cis-TeT~CI2' the geometry around the tellurium atom shows deviations from a regular square planer configuration with the Te-S and Te-Cl planes intersecting at an angle of 11 ° -12°, while the S-Te-S bond angles are 93°_95°.…”