Tritellurium dichloride

Tritellurium dichloride
Identifiers
Properties
Te3Cl2
Molar mass 453.71 g/mol
Hazards
not listed
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Tritellurium dichloride is the inorganic compound with the formula Te3Cl2. It is one of the more stable lower chlorides of tellurium.

Preparation and properties

Te3Cl2 is a gray solid. Its structure consists of a long chain of Te atoms, with every third Te center carrying two chloride ligands for the repeat unit -Te-Te-TeCl2-.[1] It is a semiconductor with a band gap of 1.52 eV, which is larger than that for elemental Te (0.34 eV).[2] It is prepared by heating Te with the appropriate stoichiometry of chlorine.[3]

Other lower tellurium chlorides

Te2Cl2 is a yellow liquid prepared by reaction of lithium polytellurides with TeCl4. Te2Cl, also a polymer, is a metastable gray solid, tending to convert to Te3Cl2 and TeCl4.[2] Being unstable with respect to disproportionation, tellurium dichloride has not been isolated as a solid, but has been characterised as the main component of the vapor formed with TeCl4 and hot Te.[4]

Although TeCl2 has not been isolated, its complexes are well characterized. They are prepared by treating tellurium dioxide with hydrochloric acid in the presence of thioureas. The thiourea serves both as a ligand and as a reductant, converting Te(IV) to Te(II).

Structure of trans-[TeCl2(SC(NMe2)2)2] (H atoms omitted).[5]

References

  1. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0-08-037941-9.
  2. 1 2 Zhengtao Xu "Recent Developments in Binary Halogen–Chalcogen Compounds, Polyanions and Polycations" in Handbook of Chalcogen Chemistry: New Perspectives in Sulfur, Selenium and Tellurium, Francesco Devillanova, Editor, 2006, RSC. pp. 381-416. Royal Society doi:10.1039/9781847557575-00455
  3. ↑ R. Kniep, D. Mootz, A. Rabenau "Zur Kenntnis der Subhalogenide des Tellurs" Zeitschrift für anorganische und allgemeine Chemie 1976, Volume 422, pages 17–38. doi:10.1002/zaac.19764220103
  4. ↑ Liv Fernholt, Arne Haaland , Hans V. Volden, Rüdiger Kniep "The molecular structure of tellurium dichloride, TeCl2, determined by gas electron diffraction" Journal of Molecular Structure 1985, volume 128, pages 29-31.doi:10.1016/0022-2860(85)85037-7
  5. ↑ O. Foss, K. Maartmann-Moe (1986). "Crystal and Molecular Structures of trans Square-Planar Complexes of Tellurium Dichloride, Dibromide and Diiodide with Tetramethylthiourea, TeL2X2. Bond Lengths in Centrosymmetric Tellurium(II) Complexes". Acta Chemica Scandinavica A. 40: 675. doi:10.3891/acta.chem.scand.40a-0675.
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