Potassium osmate is the inorganic compound with the formula K2[OsO2(OH)4]. This diamagnetic purple salt contains osmium in the VI (6+) oxidation state.[1] When dissolved in water a red solution is formed. When dissolved in ethanol, the salt gives a pink solution, and it gives a blue solution when dissolved in methanol.[1] The salt gained attention as a catalyst for the asymmetric dihydroxylation of olefins.[2]
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| Other names
Potassium osmate(VI) dihydrate
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3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.157.189 |
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CompTox Dashboard (EPA)
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| Properties | |
| H4K2O6Os | |
| Molar mass | 368.42 |
| Appearance | purple solid |
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| H301, H311, H330, H331 | |
| P260, P261, P264, P270, P271, P280, P284, P301+P310, P302+P352, P304+P340, P310, P311, P312, P320, P321, P322, P330, P361, P363, P403+P233, P405, P501 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Structure
editThe complex anion is octahedral. Like related d2 dioxo 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.
Preparation
editThe compound was first reported by Edmond Frémy in 1844.[4] Potassium osmate is prepared by reducing osmium tetroxide with ethanol:[5]
- 2 OsO4 + C2H5OH + 5 KOH → CH3CO2K + 2 K2[OsO2(OH)4]
Alkaline oxidative fusion of osmium metal also affords this salt.[1]
See also
editReferences
edit- ^ a b c F. Albert Cotton; Geoffrey Wilkinson (1966). Advanced Inorganic Chemistry: A Comprehensive Treatise. New York, Interscience Publishers. p. 1007.
- ^ Li, Guigen; Chang, Han-Ting; Sharpless, K. Barry (1996). "Catalytic Asymmetric Aminohydroxylation (AA) of Olefins". Angew. Chem. Int. Ed. Engl. 35 (4): 451–4. doi:10.1002/anie.199604511.
- ^ 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" Journal für Praktische Chemie 1844 vol.33, 406-416. doi:10.1002/prac.18440330160
- ^ John M. Malin (1980). "Potassium Tetrahydroxodioxoosmate(VI) and trans ‐Bis(Ethylenediamine)Dioxoosmium(VI) Chloride". Potassium Tetrahydroxodioxoosmate(VI) and trans-Bis(Ethylenediamine)Dioxoosmium(VI) Chloride. Inorganic Syntheses. Vol. 20. pp. 61–63. doi:10.1002/9780470132517.ch18. ISBN 9780470132517.