Hydrogen telluride

Hydrogen telluride
IUPAC name

hydrogen telluride
Other names

hydrotelluric acid
tellane
tellurium hydride
Identifiers
CAS number 7783-09-7 Y
PubChem 21765
Properties
Molecular formula 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 [1]
Boiling point

−2.2 °C (unstable above -2 °C)
Solubility in water 0.70 g/100 mL
Acidity (pKa) 2.6
Structure
Molecular shape bent
Thermochemistry
Std enthalpy of
formation ΔfHo298		 0.7684 kJ/g
Hazards
Main hazards toxic
Related compounds
Other anions H2O
H2S
H2Se
H2Po
Other cations Na2Te
Ag2Te
Related compounds telluric acid
tellurous acid
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Hydrogen telluride (tellurane) is the inorganic compound with the formula H2Te. The simplest hydride of tellurium, it is rarely encountered because of it decomposes rapidly to the constituent elements. 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]

Contents

Synthesis

H2Te is prepared by the acidification of salts of Te2−, such as Al2Te3 and Na2Te.[3] Na2Te can be generated by the reaction of Na and Te in anhydrous ammonia. The intermediate in the acidification, HTe− is a stable anion. Sodium hydrogen telluride, NaHTe, can be made by reducing tellurium with NaBH4.[3]

Properties

H2Te is an endothermic compound, unstable in air and easily oxidised to water and elemental tellurium:[4]

2 H2Te + O2 → 2 H2O + 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.[4] It reacts with many metals to form tellurides.[5]

See also

References

  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 Nicola Petragnani; Hélio A. Stefani (2007). Tellurium in organic synthesis. Best synthetic methods (2nd ed.). Academic Press. p. 6. ISBN 0080453104. 
  4. ^ a b Egon Wiberg; Arnold Frederick Holleman (2001). Nils Wiberg. ed. Inorganic chemistry. Academic Press. p. 589. ISBN 0123526515. 
  5. ^ Henry Enfield Roscoe; Carl Schorlemmer (1878). A treatise on chemistry. 1. Appleton. pp. 367–368.