| Antimony trioxide |
 |
| General |
| Other names |
Antimony(III) oxide
Antimony sesquioxide
Antimonous oxide |
| Molecular formula |
Sb2O3 |
| Molar mass |
291.52 g/mol |
| Appearance |
white solid |
| CAS number |
[1309-64-4] |
| Properties |
| Density and phase |
5.2 g/cm3, α-form |
| Solubility in water |
1.4 mg/100 ml (30 °C) |
| Melting point |
656 °C |
| Boiling point |
1425 °C |
| Acidity (pKa) |
? |
| Basicity (pKb) |
? |
| Structure |
Coordination
geometry |
? |
| Crystal structure |
cubic (α) <570 °C
orthorhombic (β) >570 °C |
| Dipole moment |
zero |
| Thermodynamic data |
Std enthalpy of
formation ΔfHo298 |
? kJ/mol |
Standard molar
entropy So298 |
? J·K−1·mol−1 |
| Hazards |
| MSDS |
External MSDS |
| EU classification |
Harmful (Xn)
Carc. Cat. 3 |
| R-phrases |
R40 |
| S-phrases |
S2, S22, S36/37 |
| Supplementary data page |
Structure and
properties |
n, εr, etc. |
Thermodynamic
data |
Phase behaviour
Solid, liquid, gas |
| Spectral data |
UV, IR, NMR, MS |
| Related compounds |
| Other anions |
Antimony trisulfide |
| Other cations |
Arsenic trioxide
Bismuth trioxide |
| Related compounds |
Diantimony tetraoxide
Antimony pentoxide |
Except where noted otherwise, data are given for
materials in their standard state (at 25°C, 100 kPa)
|
Antimony trioxide is the most important commercial compound of antimony.
Preparation
- Burning elemental antimony in air
- Roasting antimonide minerals (main industrial route)
Chemical properties
Antimony trioxide is an amphoteric oxide, dissolving in alkaline solution to give antimonites and in acid solution to given a range of polyantimonous acids. It can be readily oxidized to antimony pentoxide or other antimony(V) compounds, but is also easily reduced to antimony, sometimes with production of stibine.
Uses
The annual consumption of antimony trioxide in the United States is approximately 10000 tonnes.
Toxicology
Antimony trioxide is only weakly absorbed by the digestive system, and the main route of exposure is by inhalation of the dust. The elimination of antimony from the body is slow, leading to a risk of chronic toxicity. Acute poisoning is rare, and the signs are fairly non-characteristic (vomiting, abdominal pain, irritation of the mucous membranes, diarrhea, cardiac irregularities).
Chronic poisoning by antimony trioxide is sometimes found in exposed workers. The main signs are irritation of the respiratory tract and of the skin and a characteristic pneumoconosis which is visible on chest X-rays.
Antimony trioxide is known to pass into breast milk and to transverse the placenta. Exposed female worker have a higher incidence than usual of menstrual problems and of late-term miscarriages; their children develop slower than usual during the first twelve months of life.
Bibliography
Institut national de recherche et de sécurité (INRS), Fiche toxicologique nº 198 : Trioxyde de diantimoine, 1992.
External links
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