Tellurium trioxide

Tellurium trioxide

Names
Other names tellurium(VI) oxide
Identifiers
CAS Number	13451-18-8
3D model (Jmol)	Interactive image
ChemSpider	75319 Y
ECHA InfoCard	100.033.277
PubChem	83481
InChI InChI=1S/O3Te/c1-4(2)3 Y Key: IIXQANVWKBCLEB-UHFFFAOYSA-N Y InChI=1/O3Te/c1-4(2)3 Key: IIXQANVWKBCLEB-UHFFFAOYAH
SMILES O=[Te](=O)=O
Properties
Chemical formula	TeO3
Molar mass	175.6 g/mol
Appearance	yellow-orange crystals (α-TeO3)
Density	5.07 g/cm³, solid
Melting point	430 °C (806 °F; 703 K)
Hazards
EU classification (DSD)	not listed
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Tellurium trioxide (TeO₃) is an inorganic chemical compound of tellurium and oxygen. In this compound, tellurium is in the +6 oxidation state.

There are two forms, yellow-red α-TeO₃ and grey, rhombohedral, β-TeO₃ which is less reactive.
α-TeO₃ has a structure similar to FeF₃ with octahedral TeO₆ units that share all vertices.

α-TeO3 can be prepared by heating orthotelluric acid, Te(OH)₆, at over 300°C . The β-TeO₃ form can be prepared by heating α-TeO₃ in a sealed tube with O₂ and H₂SO₄.
α-TeO₃ is unreactive to water but is a powerful oxidising agent when heated. With alkalis it forms tellurates.
α-TeO₃ when heated loses oxygen to form firstly Te₂O₅ and then TeO₂.