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Sodium telluride
	File:Sodium telluride.jpg
Other names	Disodium telluride
Identifiers
CAS number	12034-41-2
Properties
Molecular formula	Na2Te
Molar mass	173.58 g/mol
Appearance	white powder,; hygroscopic
Density	2.90 g/cm3, solid
Melting point	953°C
Solubility in water	very soluble
Hazards
EU classification	not listed
NFPA 704	0 2 1
	Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
	Infobox references

Sodium telluride is the chemical compound with the formula Na₂Te. This salt is the conjugate base of the thermally unstable acid hydrogen telluride, but it is usually prepared by reduction of tellurium with sodium. Na₂Te is a challenging material to handle because it is very sensitive to air. Air oxidizes it initially to polytellurides, which have the formula Na₂Te_x (x > 1), and ultimately Te metal. Samples of Na₂Te, which are colourless when absolutely pure, generally appear purple or gray due to the effects of air oxidation.

[edit] Synthesis, structure, and solution properties

The synthesis is typically conducted using ammonia as the solvent.

Na₂Te, like many related compounds with the formula M₂X, adopts the antifluorite structure. Thus, in solid Na₂Te each Te^2- ion is surrounded by eight Na⁺ ions and each Na⁺ ion is surrounded by four Te^2- ions.^[1]

Simple salts of the type M₂X, where X is a monoatomic anion, are not typically soluble in any solvent because they have a high lattice energy. Upon addition of water - even moist air - or treatment with alcohols, Te^2- protonates:

Na₂Te + H₂O → NaHTe + NaOH

Because of this reaction, many processes attributed to Na₂Te may involve NaHTe (CAS# 65312-92-7), which is more soluble and formed readily.

[edit] Applications in organic chemistry

Na₂Te finds use in organic synthesis, both as a reagent for reductions and as a source of Te in the synthesis of organotellurium compounds.^[2] aryl halides are substituted to diaryl tellurides, as illustrated by the synthesis of dinaphthyltelluride:

Na₂Te + 2 C₁₀H₇I → (C₁₀H₇)₂Te + 2 NaI

Na₂Te reacts with 1,3-diynes to give the corresponding tellurophene, which are structurally analogous to thiophenes:

Na₂Te + RC≡C-C≡CR + 2 H₂O → TeC₄R₂H₂ + 2 NaOH

As a reducing agent, Na₂Te converts nitro groups to amines and will cleave certain C-X bonds.^[2]

[edit] References

^ Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.
^ ^a ^b ”Sodium Telluride” Dittmer, D. C. in Encyclopedia of Reagents for Organic Synthesis © 2001. DOI: 10.1002/047084289X.rs103.

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[0] Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.

[ditt-1] ”Sodium Telluride” Dittmer, D. C. in Encyclopedia of Reagents for Organic Synthesis © 2001. DOI: 10.1002/047084289X.rs103.

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