Chromium trioxide
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| Chromium trioxide | |
|---|---|
-oxid.jpg/200px-Chrom(VI)-oxid.jpg) |
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| IUPAC name | Chromium(VI) oxide |
| Other names | Chromium trioxide |
| Identifiers | |
| CAS number | [1333-82-0] |
| RTECS number | GB6650000 |
| SMILES | O=Cr(=O)(O) |
| Properties | |
| Molecular formula | CrO3 |
| Molar mass | 99.994 g/mol |
| Appearance | Dark red solid |
| Density | 2.70 g/cm3, solid |
| Melting point |
197 °C |
| Boiling point |
250 °C, decomposes |
| Solubility in water | 63 g/100 mL |
| Hazards | |
| EU classification | Oxidizer (O), very toxic (T+), dangerous for the environment (N) |
| NFPA 704 |
 0
3
1
OX
|
| R-phrases | R45 R46 R9 R24/25 R26 R35 R42/43 R48/23 R62 R50/53 |
| S-phrases | S53 S45 S60 S61 |
| 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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The acid anhydride of chromic acid is chromium trioxide or chromium(VI) oxide; industrially, this compound is sometimes sold as "chromic acid".[1] This compound is an intensely-colored dark red/orange brown, water-soluble, granular solid which is stable by itself, but is a strong oxidant which will react when mixed with many things that can be oxidized. Ethanol, for example, will ignite on contact with it.
Contents |
[edit] Production
Chromium trioxide is produced commercially by the reaction of sodium dichromate with concentrated sulfuric acid.[1]
[edit] Structure and chemistry
Chromium trioxide consists of chains of tetrahedrally coordinated chromium atoms that share vertices. Each chromium atom therefore has "half share of two oxygen atoms" and two oxygen atoms that are not shared, giving an overall stoichiometry of 1:3.[2]
Chromium trioxide decomposes above 197°C liberating oxygen eventually giving Cr2O3. The reaction of chromium trioxide with organic substances is potentially explosive. In spite of this, CrO3 is used in organic chemistry as an oxidant, often dissolved in acetic acid,[2] or acetone in the case of the Jones oxidation.
[edit] Safety
Chromium trioxide is highly toxic, corrosive, and carcinogenic.[3]
Chorium trioxide may cause cancer and/or heritable genetic damage. It is explosive when mixed with combustible material. It is toxic in contact with skin and if swallowed and very toxic by inhalation. CrO3 causes severe burns and may cause sensitisation by inhalation and skin contact. It is also toxic: danger of serious damage to health by prolonged exposure through inhalation. There is a possible risk of impaired fertility. CrO3 is very toxic to aquatic organisms may cause long-term adverse effects in the aquatic environment.
[edit] References
- ^ a b Chromium Trioxide. Chemicalland21.
- ^ a b Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999). Advanced Inorganic Chemistry (6th Edn.) New York:Wiley-Interscience. ISBN 0-471-19957-5.
- ^ Chromium Trioxide (MSDS). J. T. Baker. Retrieved on 2007-09-13.
