Wikipedia

Potassium osmyl oxalate

Potassium osmyl oxalate
Identifiers
3D model (JSmol)
ChemSpider
  • InChI=1S/2C2H2O4.2K.2O.Os/c2*3-1(4)2(5)6;;;;;/h2*(H,3,4)(H,5,6);;;;;/q;;2*+1;;;+2/p-4
    Key: QKOSVFDASGVBMI-UHFFFAOYSA-J
  • C(=O)(C(=O)[O-])[O-].C(=O)(C(=O)[O-])[O-].O=[Os+2]=O.[K+].[K+]
Properties
K2(OsO2)(C2O4)2
Molar mass 276.5 g/mol
soluble
Structure[1]
Triclinic, mS20
P1
a = 6.545 Å, b = 6.835 Å, c = 7.595 Å
α = 85.76°, β = 65.33°, γ = 71.14°
1
distorted octahedral
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Potassium osmyl oxalate (also known as potassium dioxalatodioxoosmate or potassium dioxobisoxalatoosmate), is an organic chemical compound containing osmium in the +6 oxidation state, with the chemical formula K2[OsO2(C2O4)2]. It is an example of an osmyl derivative, and it forms a dihydrate.

Synthesis

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There are a few different routes to prepare potassium osmyl oxalate. The simplest method involves reacting oxalic acid with potassium osmate.[2]

K2[OsO2(OH)4] + 2H2C2O4 → K2(OsO2)(C2O4)2 + 4H2O

It can also be produced by reducing osmium tetroxide in potassium hydroxide with oxalic acid.[2][3]

OsO4 + 2KOH + 3H2C2O4 → K2(OsO2)(C2O4)2 + 2CO2 + 4H2O

Addition of potassium oxalate to a solution of potassium osmyl chloride will also yield the osmyl oxalate as a precipitate.[2]

K2(OsO2)Cl4 + 2K2C2O4 → K2(OsO2)(C2O4)2 + 4KCl

Properties

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As with most osmyl complexes, potassium osmyl oxalate contains a linear O=Os=O unit at its center. The osmyl radical has an absorption band of 868 cm-1 in the infrared spectrum, while in the Raman spectrum, this absorption band appears at 910 cm-1.[1]

Potassium osmyl oxalate is stable in dry air at room temperature. While it is soluble in water and acids, it slowly decomposes, by which the osmyl species disproportionates to the dioxide and the tetroxide. In sulfuric acid, this disproportionation happens rapidly. The compound is most stable when dissolved in dimethylformamide and dimethylsulfoxide. It is insoluble in ethanol and acetone.[1]

Applications

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Potassium osmyl oxalate containing the synthetic Os-191 radioisotope was used for angiocardiography in children's hospitals.[4][5]

References

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  1. ^ a b c Burvikova, Y.N; Lin’ko, I.V.; Venskovskiĭ, N.U. (2007). "Crystal Structure and Properties of K2[OsO2(C2O4)2] · 2H2O". Crystallography Reports. 52 (5): 801–804. doi:10.1134/S1063774507050082.
  2. ^ a b c J. Newton Friend (1920). "Osmium and its compounds". A textbook of inorganic chemistry, vol.IX Part I Cobalt, Nickel, and The Elements of The Platinum Group (PDF). London: Charles Griffin and Company, Limited. pp. 223–224. Retrieved 5 August 2025.
  3. ^ Cotton, S. A. (1997). "Ruthenium and Osmium". Chemistry of Precious Metals (PDF). Rutland, UK: Blackie Academic & Professional. p. 70. Retrieved 19 August 2025.
  4. ^ Packard, Alan B.; Day, Pamela J.; Treves, S.T. (1995). "An improved 191Os/191mIr generator using a hybrid anion exchanger". Nuclear Medicine and Biology. 22 (7): 887–891. doi:10.1016/0969-8051(95)00037-X. PMID 8547886.
  5. ^ Knapp F.F. Jr.; Callahan, A.P.; Mrzadeh, C. Brihaye; Guillaume, M. The Development of New Radionuclide Generator Systems for Nuclear Medicine Applications (Report). Oak Ridge National Laboratory. p. 6.