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Hydrotelluric acid

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 (Jmol)
ChEBI
ChemSpider
ECHA InfoCard 100.029.073
EC Number 236-813-4
PubChem CID
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)
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).
N  (what is YesYN ?)
Infobox references

Hydrogen telluride (tellane) is the inorganic compound with the formula H2Te. A hydrogen chalcogenide and the simplest hydride of tellurium, it is rarely encountered because it decomposes rapidly to its constituent elements. However, 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.

H2Te is prepared by the acidification of salts of Te2−, such as Al2Te3 and Na2Te. 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 NaBH
4
.

Tellurium hydrides is usually prepared in the laboratory by hydrolysis of the telluride derivatives of electropositive metals. Typical is the hydrolysis of aluminum telluride:

Magnesium and alkali metal tellurides can also be hydrolyzed. Usually these procedures require acid since the H2Te is rather acidic. Electrolytic methods have been developed.

H
2
Te
is an endothermic compound, unstable in air and easily oxidised to water and elemental tellurium:


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