Antimony trioxide
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| Antimony trioxide | |
|---|---|
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| 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 ΔfH |
? kJ/mol |
| Standard molar entropy S |
? 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) Infobox disclaimer and references |
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Antimony trioxide is the most important commercial compound of antimony.
Contents |
[edit] Preparation
- Burning elemental antimony in air
- Roasting antimonide minerals (main industrial route)
[edit] 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.
[edit] Uses
The annual consumption of antimony trioxide in the United States is approximately 10000 tonnes.
- Flame retardant for textiles and polymers
- Opacifying agent for glasses, ceramics and enamels
- Pigment antimony white
[edit] 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 in the form of pneumoconiosis with repeated inhalation exposures. Acute poisoning is very rare, and the signs are fairly non-characteristic (vomiting, abdominal pain, irritation of the mucous membranes, diarrhea, cardiac irregularities). These symptoms are more often associated with ingestion of other more water soluble compounds.
Chronic poisoning by antimony trioxide is also rare, but 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 only in very small amounts. One study of exposed female workers suggested a higher incidence than usual of menstrual problems and of late-term miscarriages; also their children may have developed slower than usual during the first twelve months of life, although this study is inconclusive. A more recent developmental study in rodents did not confirm an effect on mammalian development.
[edit] Bibliography
Institut national de recherche et de sécurité (INRS), Fiche toxicologique nº 198 : Trioxyde de diantimoine, 1992.
Inhalation Developmental Toxicity Studies In Rats With Antimony Trioxide (Sb2O3). Newton PE; Schroeder RE; Zwick L; Serex T Toxicologist 2004 Mar;78(1-S):38
