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Hydrogen telluride

Liquid hydrogen telluride in a test tube
Tellurium, Te  Hydrogen, H
Names
IUPAC name hydrogen telluride
Other names hydrotelluric acid tellane tellurium hydride dihydrogen telluride
Identifiers
CAS Number	7783-09-7
3D model (JSmol)	Interactive image
ChEBI	CHEBI:30452
ChemSpider	20455
ECHA InfoCard	100.029.073
EC Number	236-813-4
PubChem CID	21765
UNII	7F4735942K
CompTox Dashboard (EPA)	DTXSID20228446
InChI InChI=1S/H2Te/h1H2Key: VTLHPSMQDDEFRU-UHFFFAOYSA-N
SMILES
Properties
Chemical formula	H2Te
Molar mass	129.6158 g mol
Appearance	colourless gas
Odor	Pungent, resembles rotting garlic or leeks
Density	3.310 g/L, gas 2.57 g/cm (−20 °C, liquid)
Melting point	−49 °C (−56 °F; 224 K)
Boiling point	−2.2 °C (28.0 °F; 270.9 K) (unstable above −2 °C)
Solubility in water	0.70 g/100 mL
Acidity (pKa)	2.6
Conjugate acid	Telluronium
Conjugate base	Telluride
Structure
Molecular shape	bent
Thermochemistry
Std enthalpy of formation (ΔfH298)	0.7684 kJ/g
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Highly toxic and flammable
NFPA 704 (fire diamond)	4 4 1
Related compounds
Other anions	H2O H2S H2Se H2Po
Other cations	Na2Te Ag2Te K2Te Rb2Te Cs2Te
Related compounds	telluric acid tellurous acid stibine
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). N verify (what is  ?) Infobox references

Hydrogen telluride 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 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.

Synthesis

Electrolytic methods have been developed.

H₂Te can also be prepared by hydrolysis of the telluride derivatives of electropositive metals. The typical hydrolysis is that of aluminium telluride:

Al₂Te₃ + 6 H₂O → 2 Al(OH)₃ + 3 H₂Te

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

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

Properties

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

H
₂Te → H
₂ + Te

Light accelerates the decomposition. It is unstable in air, being oxidized to water and elemental tellurium:

2 H
₂Te + O
₂ → 2 H
₂O + 2 Te

It is almost as acidic as phosphoric acid (K_a = 8.1×10), having a K_a value of about 2.3×10. It reacts with many metals to form tellurides.

See also

• Dimethyl telluride

References

1. Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, Florida: 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. ^ 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. ^ Nicola Petragnani; Hélio A. Stefani (2007). Tellurium in organic synthesis. Best synthetic methods (2nd ed.). Academic Press. p. 6. ISBN 978-0-08-045310-1.
6. ^ 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. Vol. 1. Appleton. pp. 367–368.

• Hydrogen compounds
• Triatomic molecules
• Tellurides