Phosphorus tetroxide
General | |||||||
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Surname | Phosphorus tetroxide | ||||||
Molecular formula | P 2 O 4 | ||||||
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properties | |||||||
Molar mass | 125.96 g mol −1 | ||||||
Physical state |
firmly |
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density |
2.54 g cm −3 |
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Melting point |
> 100 ° C |
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As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . |
Phosphorus tetroxide ( phosphorus tetraoxide, diphosphorus tetraoxide ) is a chemical compound made up of the elements phosphorus and oxygen and is one of the oxides of phosphorus. The empirical formula is given as P 2 O 4 , although this does not quite do justice to the structure or the stoichiometry of the compound.
Extraction and presentation
Phosphorus tetroxide can be obtained by thermal decomposition of phosphorus trioxide :
- Phosphorus trioxide disproportionates to phosphorus and phosphorus tetroxide above 210 ° C.
Furthermore can the phosphorus trioxide by a controlled oxidation with oxygen in a carbon tetrachloride - solution are converted into phosphorus tetroxide.
If phosphorus pentoxide is carefully reduced with red phosphorus at 450–525 ° C, phosphorus tetroxide is formed.
properties
Phosphorus tetroxide is a colorless, solid mixed oxide that crystallizes differently depending on the manufacturing process . The so-called α-form forms rhombohedral crystals and consists of P 4 O 8 and P 4 O 9 - molecules in varying amounts. Instead of the above-mentioned empirical formula are added to this form of Phosphortetroxids the ratio formula P 4 O from 8.1 to 9.0 at. Monoclinic crystallizes the β form, consisting of P 4 O 7 and P 4 O 8 . The ratio formula here is P 4 O 7.7–8.0 .
Phosphorus tetroxide reacts with water ( hydrolysis ) to form phosphonic and phosphoric acid .
Individual evidence
- ↑ a b Entry on phosphorus oxides. In: Römpp Online . Georg Thieme Verlag, accessed on September 30, 2014.
- ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
- ↑ a b c Ralf Steudel : Chemistry of Non-Metals, Syntheses - Structures - Bonding - Use , 4th Edition, 2014 Walter de Gruyter GmbH & Co. KG, Berlin / Boston, ISBN 978-3-11-030439-8 , p. 408-409, (accessed via De Gruyter Online).