Potassium osmate
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| Names | |
|---|---|
| Other names
Potassium osmate(VI) dihydrate
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| Identifiers | |
| ECHA InfoCard | 100.157.189 |
| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| H4K2O6Os | |
| Molar mass | 368.42 |
| Appearance | purple solid |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Potassium osmate is the inorganic compound with the formula K2[OsO2(OH)4]. It contains Osmium in the VI (6+) oxidation state. It is a diamagnetic purple salt that gained attention as a catalyst for the asymmetric dihydroxylation of olefins.[1] When dissolved in water a pink solution is formed.[2] But when dissolved in methanol the solution is blue.[2]
Like related d2 complexes, the oxo ligands are trans.[3] The Os=O and Os-OH distances are 1.75(2) and 1.99(2) Å, respectively. It is a relatively rare example of a metal oxo complex that obeys the 18e rule. The compound was first reported by Edmond Frémy in 1844.[4]
Osmate salts can be produced by reducing perosmates using alcohol. Osmium tetroxide is dissolved in potassium hydroxide water solution to produce K2[OsO4(OH)2], which is then reduced to potassium osmate.[2] Another way to make this is by alkaline oxidative fusion of osmium metal.[2]
References
- ^ Li, Guigen; Chang, Han-Ting; Sharpless, K. Barry "Catalytic asymmetric aminohydroxylation (AA) of olefins" Angew. Chem. Int. Ed. Engl. 1996, volume 35, pp. 451-4. doi:10.1002/anie.199604511
- ^ a b c d F. Albert Cotton; Geoffrey Wilkinson (1966). Advanced Inorganic Chemistry: A Comprehensive Treatise. p. 1007.
- ^ R. K. Murmann, C. L. Barnes "Redetermination of the crystal structure of potassium trans-(dioxo)-tetra(hydroxo)osmate(VI), K2[Os(OH)4(O)2]" Z. Kristallogr. NCS 217, 2002, pp. 303–304. doi:10.1524/ncrs.2002.217.jg.303
- ^ Frémy, E. "Ueber das Osmium" J. Prakt. Chem. 1844 vol.33, 406-416. doi:10.1002/prac.18440330160