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

作者：Shlykov Sergey A^*; Oberhammer Heinz; Titov Anton V; Giricheva Nina I; Girichev Georgiy V

来源：European Journal of Inorganic Chemistry, 2008, (33): 5220-5227.

DOI：10.1002/ejic.200800700

• Tellurium halides
• Gas-phase electron diffraction
• Mass spectrometry
• Quantum chemical calculations

The sublimation processes of TeBI(4) at 471(5) K and Tel(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 1(2)(g) and Te(s). A very small contribution of 3.3 +/- 2.1 mol-% of gaseous Tel(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) angstrom and angle(g)Br-Te-Br = 99.0(6)circle for TeBr(2) and r(g)(Te-I) = 2.693(9) angstrom and angle(g)(I-Te-I) = 103.1(22)degrees 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.

• 出版日期2008-11