Chemistry:Tellurium compounds

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Short description: Any chemical compound containing at least one tellurium atom
See also the categories Tellurium compounds and Telluride minerals

Tellurium compounds are compounds containing the element tellurium (Te). Tellurium belongs to the chalcogen (group 16) family of elements on the periodic table, which also includes oxygen, sulfur, selenium and polonium: Tellurium and selenium compounds are similar. Tellurium exhibits the oxidation states −2, +2, +4 and +6, with +4 being most common.[1]

Tellurides

Reduction of Te metal produces the tellurides and polytellurides, Ten2−. The −2 oxidation state is exhibited in binary compounds with many metals, such as zinc telluride, ZnTe, produced by heating tellurium with zinc.[2] Decomposition of ZnTe with hydrochloric acid yields hydrogen telluride (H2Te), a highly unstable analogue of the other chalcogen hydrides, H2O, H2S and H2Se:

ZnTe + 2 HCl → ZnCl2 + H2Te

H2Te is unstable, whereas salts of its conjugate base [TeH]− are stable.

Halides

Structure of tellurium tetrachloride, tetrabromide and tetraiodide

The +2 oxidation state is exhibited by the dihalides, TeCl2, TeBr2 and TeI2. The dihalides have not been obtained in pure form,[3]:274 although they are known decomposition products of the tetrahalides in organic solvents, and the derived tetrahalotellurates are well-characterized:

Te + X2 + 2 X− → TeX2−4

where X is Cl, Br, or I. These anions are square planar in geometry.[3]:281 Polynuclear anionic species also exist, such as the dark brown Te2I2−6,[3]:283 and the black Te4I2−14.[3]:285

With fluorine Te forms the mixed-valence Te2F4 and TeF6. In the +6 oxidation state, the –OTeF5 structural group occurs in a number of compounds such as HOTeF5, B(OTeF5)3, Xe(OTeF5)2, Te(OTeF5)4 and Te(OTeF5)6.[4] The square antiprismatic anion TeF2−8 is also attested.[5] The other halogens do not form halides with tellurium in the +6 oxidation state, but only tetrahalides (TeCl4, TeBr4 and TeI4) in the +4 state, and other lower halides (Te3Cl2, Te2Cl2, Te2Br2, Te2I and two forms of TeI). In the +4 oxidation state, halotellurate anions are known, such as TeCl2−6 and Te2Cl2−10. Halotellurium cations are also attested, including TeI+3, found in TeI3AsF6.[6]

Oxocompounds

A sample of pale yellow powder
A sample of tellurium dioxide powder

Tellurium monoxide was first reported in 1883 as a black amorphous solid formed by the heat decomposition of TeSO3 in vacuum, disproportionating into tellurium dioxide, TeO2 and elemental tellurium upon heating.[7][8] Since then, however, existence in the solid phase is doubted and in dispute, although it is known as a vapor fragment; the black solid may be merely an equimolar mixture of elemental tellurium and tellurium dioxide.[9]

Tellurium dioxide is formed by heating tellurium in air, where it burns with a blue flame.[2] Tellurium trioxide, β-TeO3, is obtained by thermal decomposition of Te(OH)6. The other two forms of trioxide reported in the literature, the α- and γ- forms, were found not to be true oxides of tellurium in the +6 oxidation state, but a mixture of Te4+, OH− and O−2.[10] Tellurium also exhibits mixed-valence oxides, Te2O5 and Te4O9.[10]

The tellurium oxides and hydrated oxides form a series of acids, including tellurous acid (H2TeO3), orthotelluric acid (Te(OH)6) and metatelluric acid ((H2TeO4)n).[9] The two forms of telluric acid form tellurate salts containing the TeO2–4 and TeO6−6 anions, respectively. Tellurous acid forms tellurite salts containing the anion TeO2−3.

Other chalcogenides

A disulfide, TeS2, forms when tellurous acid (H
2TeO
3) is mixed with hydrogen sulfide, but is unstable above −20 °C.[11] In contrast, many thiotellurate anions are known, including TeS2−
3, Te(S5)x(S7)2-y (x + y = 2). Many of these arise from the action of tellurium metal on polysulfide anions,[12][13] although a solid-state synthesis is also possible.[14] Despite their similarities to sulfo-selenide anions, the thiotellurates are not catenation products; instead, the sulfur ligands coordinate to the tellurium as heavier congeners to a tellurate.[15] A thiosubtellurite, TeS2−
2, is also known. These compounds are of interest because of their potential for ionic conductivity.[16]

Analogous selenotellurates are also known.

Zintl cations

When tellurium is treated with concentrated sulfuric acid, the result is a red solution of the Zintl ion, Te2+4.[17] The oxidation of tellurium by AsF5 in liquid SO2 produces the same square planar cation, in addition to the trigonal prismatic, yellow-orange Te4+6:[5]

4 Te + 3 AsF5 → Te2+4(AsF−6)2 + AsF3
6 Te + 6 AsF5 → Te4+6(AsF−6)4 + 2 AsF3

Other tellurium Zintl cations include the polymeric Te2+7 and the blue-black Te2+8, consisting of two fused 5-membered tellurium rings. The latter cation is formed by the reaction of tellurium with tungsten hexachloride:[5]

8 Te + 2 WCl6 → Te2+8(WCl−6)2

Interchalcogen cations also exist, such as Te2Se2+6 (distorted cubic geometry) and Te2Se2+8. These are formed by oxidizing mixtures of tellurium and selenium with AsF5 or SbF5.[5]

Organotellurium compounds

Main page: Chemistry:Organotellurium chemistry

Tellurium does not readily form analogues of alcohols and thiols, with the functional group –TeH, that are called tellurols. The –TeH functional group is also attributed using the prefix tellanyl-.[18] Like H2Te, these species are unstable with respect to loss of hydrogen. Telluraethers (R–Te–R) are more stable, as are telluroxides.

Tritelluride quantum materials

Recently, physicists and materials scientists have been discovering unusual quantum properties associated with layered compounds composed of tellurium that's combined with certain rare-earth elements, as well as yttrium (Y).[19]

These novel materials have the general formula of R Te3, where "R " represents a rare-earth lanthanide (or Y), with the full family consisting of R = Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er & Tm (not yet observed are compounds containing Pm, Eu, Yb & Lu). These materials have a two-dimensional character within an orthorhombic crystal structure, with slabs of R Te separated by sheets of pure Te.[19]

It is thought that this 2-D layered structure is what leads to a number of interesting quantum features, such as charge-density waves, high carrier mobility, superconductivity under specific conditions, and other peculiar properties whose natures are only now emerging.[19]

For example, in 2022, a small group of physicists at Boston College in Massachusetts led an international team that used optical methods to demonstrate a novel axial mode of a Higgs-like particle in R Te3 compounds that incorporate either of two rare-earth elements (R = La, Gd).[20] This long-hypothesized, axial, Higgs-like particle also shows magnetic properties and may serve as a candidate for dark matter.[21]

See also

References

  1. ↑ Leddicotte, G. W. (1961). The radiochemistry of tellurium. Nuclear science series. Subcommittee on Radiochemistry, National Academy of Sciences-National Research Council. p. 5. http://library.lanl.gov/cgi-bin/getfile?rc000049.pdf. 
  2. ↑ 2.0 2.1 Roscoe, Henry Enfield; Schorlemmer, Carl (1878). A treatise on chemistry. 1. Appleton. pp. 367–368. 
  3. ↑ 3.0 3.1 3.2 3.3 Emeleus, H. J. (1990). A. G. Sykes. ed. Advances in Inorganic Chemistry. 35. Academic Press. ISBN 0-12-023635-4. 
  4. ↑ Holloway, John H.; Laycock, David (1983). "Preparations and Reactions of Inorganic Main-Group Oxide-Fluorides". in Harry Julius Emeléus. Advances in inorganic chemistry and radiochemistry. Serial Publication Series. 27. Academic Press. p. 174. ISBN 0-12-023627-3. 
  5. ↑ 5.0 5.1 5.2 5.3 Wiberg, Egon; Holleman, Arnold Frederick (2001). Nils Wiberg. ed. Inorganic chemistry. translated by Mary Eagleson. Academic Press. p. 588. ISBN 0-12-352651-5. 
  6. ↑ Xu, Zhengtao (2007). "Recent developments in binary halogen-chalcogen compounds, polyanions and polycations". in Francesco A. Devillanova. Handbook of chalcogen chemistry: new perspectives in sulfur, selenium and tellurium. Royal Society of Chemistry. pp. 457–466. ISBN 978-0-85404-366-8. https://archive.org/details/handbookchalcoge00devi_741. 
  7. ↑ Schwartz, Mel M. (2002). "Tellurium". Encyclopedia of materials, parts, and finishes (2nd ed.). CRC Press. ISBN 1-56676-661-3. 
  8. ↑ Divers, Edward; Shimosé, M. (1883). "On a new oxide of tellurium". Journal of the Chemical Society 43: 319–323. doi:10.1039/CT8834300319. https://zenodo.org/record/2170636. 
  9. ↑ 9.0 9.1 Dutton, W. A.; Cooper, W. Charles (1966). "The Oxides and Oxyacids of Tellurium". Chemical Reviews 66 (6): 657–675. doi:10.1021/cr60244a003. 
  10. ↑ 10.0 10.1 Wickleder, Mathias S. (2007). "Chalcogen-Oxygen Chemistry". in Francesco A. Devillanova. Handbook of chalcogen chemistry: new perspectives in sulfur, selenium and tellurium. Royal Society of Chemistry. pp. 348–350. ISBN 978-0-85404-366-8. https://archive.org/details/handbookchalcoge00devi_741. 
  11. ↑ Hageman, Aaron M. (2 Dec 1918). "A contribution to the chemistry of tellurium sulfide". J. Am. Chem. Soc. 41 (3): 329–341. doi:10.1021/ja01460a005. 
  12. ↑
    • Müller, Ulrich; Bubenheim, Wilfried (26 August 1999). "Synthese und Kristallstrukturen von (NEt4)2[TeS3], (NEt4)2[Te(S5)(S7)] und (NEt4)4[Te(S5)2][Te(S7)2]". Zeitschrift für anorganische und allgemeine Chemie (Wiley) 625 (9): 1522–1526. doi:10.1002/(SICI)1521-3749(199909)625:9<1522::AID-ZAAC1522>3.0.CO;2-D. 
    • Bubenheim, Wilfried; Frenzen, Gerlinde; Müller, Ulrich (June 1994). "Synthese und Kristallstrukturen von (PPh4)2[TeS3]·2CH3CN und (PPh4)2[Te(S5)2]". Zeitschrift für anorganische und allgemeine Chemie (Wiley) 620 (6): 1046–1050. doi:10.1002/zaac.19946200617. 
  13. ↑ Kysliak, Oleksandr; Beck, Johannes (2013). "Chalcogenidotellurates(IV) (TeS3)2– and (TeSe3)2– by Low-Temperature Solvothermal Synthesis from Liquid Ammonia and Methylamine". European Journal of Inorganic Chemistry (Wernheim: Wiley-VCH) 2013: 124–133. doi:10.1002/ejic.201200927. 
  14. ↑ McCarthy, Timothy J.; Xiang Zhang; Kanatzidis, Mercouri G. (June 1, 1993). "Synthesis of cesium copper sulfide CsCuS6, and Cs6Cu2(TeS3)2(S6)2 in molten cesium sulfide telluride, Cs2SxTey, salts: Novel compounds containing polychalcogenide ligands". Inorg. Chem. (American Chemical Society) 32 (13): 2944–2948. doi:10.1021/ic00065a024. 
  15. ↑
    • Duck-Young Chung; Song-Ping Huang; Kang-Woo Kim; Kanatzidis, Mercouri G. (August 1, 1995). "Discrete Complexes Incorporating Heteropolychalcogenide Ligands: Ring and Cage Structures in [Au2(TeS3)2]2-, [Ag2Te(TeS3)2]2-, and [Ag2Te(TeSe3)2]2-". Inorg. Chem. (American Chemical Society) 34 (17): 4292–4293. doi:10.1021/ic00121a003. 
    • Xiang Zhang; Kanatzidis, Mercouri G. (March 1, 1994). "The Thiotellurites A2Mn(TeS3)2 (A = Cs, Rb): New Layered Solids Based on the Pyramidal TeS2-3 Building Unit". Inorg. Chem. (American Chemical Society) 33 (6): 1238–1240. doi:10.1021/ic00084a046. 
  16. ↑ Babo, Jean-Marie; Wolff, Klaus K.; Schleid, Thomas (2013). "Two New Cesium Thiotellurates: Cs2[TeS2] and Cs2[TeS3]". Z. Anorg. Allg. Chem. (Wernheim: Wiley-VCH) 639 (15): 2875–2881. doi:10.1002/zaac.201300402. 
  17. ↑ Molnar, Arpad; Olah, George Andrew; Surya Prakash, G. K.; Sommer, Jean (2009). Superacid Chemistry (2nd ed.). Wiley-Interscience. pp. 444–445. ISBN 978-0-471-59668-4. https://archive.org/details/superacidchemist00olah. 
  18. ↑ Sadekov, I. D.; Zakharov, A. V. (1999). "Stable tellurols and their metal derivatives". Russian Chemical Reviews 68 (11): 909–923. doi:10.1070/RC1999v068n11ABEH000544. Bibcode: 1999RuCRv..68..909S. 
  19. ↑ 19.0 19.1 19.2 Yumigeta, Kentaro; Qin, Ying; Li, Han; Blei, Mark; Attarde, Yashika; Kopas, Cameron; Tongay, Sefaattin (2021). "Advances in Rare-Earth Tritelluride Quantum Materials: Structure, Properties, and Synthesis". Advanced Science 8 (12): 2004762. doi:10.1002/advs.202004762. PMID 34165898. PMC 8224454. https://www.osti.gov/servlets/purl/1816430. Retrieved 12 June 2022. 
  20. ↑ Wang, Yiping; Petrides, Ioannis; McNamara, Grant; Hosen, Md Mofazzel; Lei, Shiming; Wu, Yueh-Chun; Hart, James L.; Lv, Hongyan et al. (8 June 2022). "Axial Higgs mode detected by quantum pathway interference in R Te3". Nature 606 (7916): 896–901. doi:10.1038/s41586-022-04746-6. PMID 35676485. Bibcode: 2022Natur.606..896W. https://www.nature.com/articles/s41586-022-04746-6. Retrieved 12 June 2022. 
  21. ↑ Lea, Robert (8 June 2022). "Physicists discover never-before seen particle sitting on a tabletop". Live Science. https://www.livescience.com/magnetic-higgs-relative-discovered. 



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