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A Combined Gas‐Phase Electron Diffraction/Mass Spectrometric Study of the Sublimation Processes of TeBr 4 and TeI 4 : The Molecular Structure of Tellurium Dibromide and Tellurium Diiodide
Author(s) -
Shlykov Sergey A.,
Oberhammer Heinz,
Titov Anton V.,
Giricheva Nina I.,
Girichev Georgiy V.
Publication year - 2008
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200800700
Subject(s) - chemistry , tellurium , sublimation (psychology) , mass spectrum , electron diffraction , crystallography , molecular geometry , chalcogen , analytical chemistry (journal) , mass spectrometry , molecule , diffraction , inorganic chemistry , organic chemistry , psychology , physics , chromatography , optics , psychotherapist
The sublimation processes of TeBr 4 at 471(5) K and TeI 4 at 373(5) K were studied with a combined gas‐phase electron diffraction and mass spectrometric technique (GED/MS). The mass spectra and the analysis of the GED intensities showed that a contribution of 40(3) mol‐% TeBr 2 , 59(3) mol‐% Br 2 , and 1 mol‐% TeBr 4 was formed in the vapor over TeBr 4 (s). Solid tellurium tetraiodide decomposes to form I 2 (g) and Te(s). A very small contribution of 3.3 ± 2.1 mol‐% of gaseous TeI 2 was also determined by both GED and MS. The “metallic” Te accumulated in the solid phase vaporizes at above ca. 670 K as the predominately Te 2 molcular species. Refinement of the GED intensities resulted in r g (Te–Br) = 2.480(5) Å and ∠ g Br–Te–Br = 99.0(6)° for TeBr 2 and r g (Te–I) = 2.693(9) Å and ∠ g (I–Te–I) = 103.1(22)° for TeI 2 . The small contribution of TeBr 4 observed in the mass spectra of the vapor over TeBr 4 could not be observed in the GED data. Geometric parameters and vibrational frequencies for the tellurium dihalides TeX 2 with X = F, Cl, Br, and I were calculated with B3LYP, MP2, CCSD, and CCSD(T) methods by using aug‐cc‐pVTZ basis sets and various core potentials for the tellurium atom. Bonding properties in tellurium dihalides are discussed on the basis of natural bond orbital analyses. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)