Antimony tetroxide

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Antimony tetroxide
Sb2O4 structure.jpg
     An      O
CAS number 12786-74-2 YesY, 1332-81-6
Molecular formula SbO2; Sb2O4
Molar mass 153.7588; 307.5176 g/mol
Appearance white solid
Density 6.64 g/cm3 (orthorhombic form) [1]
Solubility in water insoluble
Refractive index (nD) 2.0
Crystal structure orthorhombic
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Related compounds
Related compounds Antimony trioxide
Antimony pentoxide
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Antimony tetroxide is an inorganic compound with the formula Sb2O4. This material, which exists as the mineral cervantite,[2] is white but reversibly yellows upon heating. The material, with empirical formula SbO2, is called antimony tetroxide to signify the presence of two kinds of Sb centers.

Formation and structure[edit]

The material forms when Sb2O3 is heated in air:[3]

Sb2O3 + 0.5 O2 → Sb2O4 ΔH = −187 kJ/mol

At 800 °C, antimony(V) oxide loses oxygen to give the same material:

Sb2O5 → Sb2O4 + 0.5 O2 ΔH = −64 kJ/mol

The material is mixed valence, containing both Sb(V) and Sb(III) centers. Two polymorphs are known, one orthorhombic (shown in the infobox) and one monoclinic.[1] Both forms feature octahedral Sb(V) centers arranged in sheets with distorted Sb(III) centers bound to four oxides.


  1. ^ a b J. Amador, E. Gutierrez Puebla, M. A. Monge, I. Rasines, and C. Ruiz Valero "Diantimony Tetraoxides Revisited" Inorganic Chemistry 1988, Volume 27, pp. 1367–1370. doi:10.1021/ic00281a011
  2. ^ "Cervantite". Webminerals. Retrieved 2009-06-06. 
  3. ^ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.