Hydrogen telluride

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Hydrogen telluride
Structural diagram of the hydrogen telluride molecule
Space-filling model of the hydrogen telluride molecule
Names
IUPAC name
hydrogen telluride
Other names
hydrotelluric acid
tellane
tellurium hydride
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.029.073
EC Number 236-813-4
UNII
Properties
H2Te
Molar mass 129.6158 g mol−1
Appearance colourless gas
Density 3.310 g/cm3, gas
2.57 g/cm3 (−20 °C, liquid)
Melting point −49 °C (−56 °F; 224 K)[1]
Boiling point −2.2 °C (28.0 °F; 270.9 K) (unstable above −2 °C)
0.70 g/100 mL
Acidity (pKa) 2.6
Structure
bent
Thermochemistry
0.7684 kJ/g
Hazards
Main hazards toxic
Related compounds
Other anions
H2O
H2S
H2Se
H2Po
Other cations
Na2Te
Ag2Te
K2Te
Rb2Te
Cs2Te
Related compounds
telluric acid
tellurous acid
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

Hydrogen telluride (tellane) is the inorganic compound with the formula H2Te. A hydrogen chalcogenide and the simplest hydride of tellurium, it is a colorless gas. Although unstable in ambient air, the gas can exist at very low concentrations long enough to be readily detected by the odour of rotting garlic at extremely low concentrations; or by the revolting odour of rotting leeks at somewhat higher concentrations. Most compounds with Te–H bonds (tellurols) are unstable with respect to loss of H2. H2Te is chemically and structurally similar to hydrogen selenide, both are acidic. The H–Te–H angle is about 90°. Volatile tellurium compounds often have unpleasant odours, reminiscent of decayed leeks or garlic.[2]

Synthesis[edit]

Electrolytic methods have been developed.[3]

H2Te can also be prepared by hydrolysis of the telluride derivatives of electropositive metals.[4] Typical is the hydrolysis of aluminium telluride:

Al2Te3 + 6 H2O → 2 Al(OH)3 + 3 H2Te

Other salts of Te2− such as MgTe and sodium telluride can also be used. Na2Te can be made by the reaction of Na and Te in anhydrous ammonia.[5] The intermediate in the hydrolysis, HTe
, can be isolated as salts as well. NaHTe, can be made by reducing tellurium with NaBH
4
.[5]

Hydrogen telluride cannot be efficiently prepared from its constituent elements, in contrast to H2Se.[3]

Properties[edit]

H
2
Te
is an endothermic compound, degrading to the elements at room temperature:

H
2
Te
H
2
+ Te

Light accelerates the decomposition. It is unstable in air, being oxidised to water and elemental tellurium:[6]

2 H
2
Te
+ O
2
→ 2 H
2
O
+ 2 Te

It is almost as acidic as phosphoric acid (Ka = 8.1×10−3), having a Ka value of about 2.3×10−3.[6] It reacts with many metals to form tellurides.[7]

See also[edit]

References[edit]

  1. ^ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3. 
  2. ^ Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4.
  3. ^ a b F. Fehér, "Hydrogen Telluride" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. pp. 438.
  4. ^ Shriver, Atkins. Inorganic Chemistry, Fifth Edition. W. H. Freeman and Company, New York, 2010; pp 407.
  5. ^ a b Nicola Petragnani; Hélio A. Stefani (2007). Tellurium in organic synthesis. Best synthetic methods (2nd ed.). Academic Press. p. 6. ISBN 0-08-045310-4. 
  6. ^ a b Egon Wiberg; Arnold Frederick Holleman (2001). Nils Wiberg, ed. Inorganic chemistry. Translated by Mary Eagleson. Academic Press. p. 589. ISBN 0-12-352651-5. 
  7. ^ Henry Enfield Roscoe; Carl Schorlemmer (1878). A treatise on chemistry. 1. Appleton. pp. 367–368.