Hydrogen telluride
| Hydrogen telluride | |
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hydrogen telluride |
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Other names
hydrotelluric acid |
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| Identifiers | |
| CAS number | 7783-09-7  |
| 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 ΔfH |
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 |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| 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 |
[edit] 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]
[edit] 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]
[edit] See also
[edit] References
- ^ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3.
- ^ Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4.
- ^ a b Nicola Petragnani; Hélio A. Stefani (2007). Tellurium in organic synthesis. Best synthetic methods (2nd ed.). Academic Press. p. 6. ISBN 0080453104.
- ^ a b Egon Wiberg; Arnold Frederick Holleman (2001). Nils Wiberg. ed. Inorganic chemistry. Academic Press. p. 589. ISBN 0123526515.
- ^ Henry Enfield Roscoe; Carl Schorlemmer (1878). A treatise on chemistry. 1. Appleton. pp. 367–368.
