Methylarsonic acid
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| Names | |
|---|---|
| Other names
methanearsonic acid | |
| Identifiers | |
| 3D model (JSmol) |
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| 4-04-00-03682 | |
| ChemSpider | |
| EC Number | 204-705-6 |
| PubChem CID |
|
| RTECS number | PA1575000 |
| UNII | |
| UN number | 1557 |
| |
| |
| Properties | |
| CH5AsO3 | |
| Molar mass | 139.97 g·mol−1 |
| Appearance | white solid |
| Melting point | 160.5 °C (320.9 °F; 433.6 K) |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Methylarsonic acid is an organoarsenic compound with the formula CH3AsO3H2. It is a colorless, water-soluble solid. Salts of this compound, e.g. disodium methyl arsonate, have been widely used in as a herbicides and fungicides in growing cotton and rice.[1]
Near physiological pH, methanearsonic acid converts to its conjugate bases, the methylarsonates. These include CH3AsO3H− and CH3AsO32-. The biomethylation of arsenic compounds is thought to start with the formation of methanearsonates. Thus, trivalent arsenic compounds are methylated to give methanearsonate. S-adenosylmethionine is the methyl donor. The methanearsonates are the precursors to cacodylates, again by the cycle of reduction (to methylarsonous acid) followed by a second methylation.[2]
Safety
Like all arsenic compounds, it is highly toxic.[2]
References
- ↑ Grund, S. C.; Hanusch, K.; Wolf, H. U. (2005), "Arsenic and Arsenic Compounds", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a03_113.pub2
- 1 2 Styblo, M.; Del Razo, L. M.; Vega, L.; Germolec, D. R.; LeCluyse, E. L.; Hamilton, G. A.; Reed, W.; Wang, C.; Cullen, W. R.; Thomas, D. J. (2000). "Comparative toxicity of trivalent and pentavalent inorganic and methylated arsenicals in rat and human cells". Archives of Toxicology. 74: 289–299. doi:10.1007/s002040000134.