Antimony tetroxide

Antimony tetroxide is an inorganic compound with the formula Sb2O4. This material, which exists as the mineral cervantite,[3] 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.

Antimony tetroxide

  Sb   O
Names
IUPAC name
antimony(III,V) oxide
Identifiers
ECHA InfoCard 100.014.161
Properties
SbO2; Sb2O4
Molar mass 153.7588; 307.5176 g/mol
Appearance white solid
Density 6.64 g/cm3 (orthorhombic form) [1]
Melting point > 930 °C (1,710 °F; 1,200 K) (decomposes)
Boiling point decomposes
insoluble
2.0
Structure
orthorhombic
Hazards
NFPA 704 (fire diamond)
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
2
0
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 0.5 mg/m3 (as Sb)[2]
REL (Recommended)
 TWA 0.5 mg/m3 (as Sb)[2]
Related compounds
Related compounds
 Antimony trioxide
Antimony pentoxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Formation and structure

The material forms when Sb2O3 is heated in air:[4]

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.

References
  1. Amador, J.; Puebla, E. Gutierrez; Monge, M. A.; Rasines, I.; Valero, C. Ruiz (1988). "Diantimony Tetraoxides Revisited". Inorganic Chemistry. 27: 1367–1370. doi:10.1021/ic00281a011.
  2. NIOSH Pocket Guide to Chemical Hazards. "#0036". National Institute for Occupational Safety and Health (NIOSH).
  3. "Cervantite". Webminerals. Retrieved 2009-06-06.
  4. Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
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