Potassium osmate

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 pink solution is formed but when dissolved in methanol, the salt gives a blue solution.[1] The salt gained attention as a catalyst for the asymmetric dihydroxylation of olefins.[2]

Potassium osmate
Names
Other names
Potassium osmate(VI) dihydrate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.157.189
EC Number
  • 243-247-1
UNII
Properties
H4K2O6Os
Molar mass 368.42
Appearance purple solid
Hazards
GHS pictograms
GHS Signal word Danger
H301, H311, H330, H331
P260, P261, P264, P270, P271, P280, P284, P301+310, P302+352, P304+340, P310, P311, P312, P320, P321, P322, P330, P361, P363, P403+233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Structure

The 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

The compound was first reported by Edmond Frémy in 1844.[4]

Potassium osmate is prepared by reducing perosmates using alcohol:[5]

2 OsO4 + C2H5OH + 3 KOH → CH3CO2K + 2 K2[OsO2(OH)4]

Alkaline oxidative fusion of osmium metal also affords this salt.[1]

References
  1. F. Albert Cotton; Geoffrey Wilkinson (1966). Advanced Inorganic Chemistry: A Comprehensive Treatise. p. 1007.
  2. Li, Guigen; Chang, Han-Ting; Sharpless, K. Barry (1996). "Catalytic Asymmetric Aminohydroxylation (AA) of Olefins". Angew. Chem. Int. Ed. Engl. 35: 451–4. doi:10.1002/anie.199604511.CS1 maint: uses authors parameter (link)
  3. 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
  4. Frémy, E. "Ueber das Osmium" Journal für Praktische Chemie 1844 vol.33, 406-416. doi: 10.1002/prac.18440330160
  5. John M. Malin (1980). "Potassium Tetrahydroxodioxoosmate(VI) and trans-Bis(Ethylenediamine)Dioxoosmium(VI) Chloride". Inorganic Syntheses. 20: 61–63. doi:10.1002/9780470132517.ch18.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.