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Chloroosmic acid
View on Wikipedia Solution of chloroosmic acid
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| Names | |
|---|---|
| IUPAC name
Dihydrogen hexachloroosmate(2-)
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Other names
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.043.797 |
| EC Number |
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PubChem CID
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| Properties | |
| Cl6H2Os | |
| Molar mass | 404.95 g·mol−1 |
| Appearance | Reddish-purple or black crystalline solid.[1][2] Yields greenish yellow to reddish brown solutions[2][3] |
| Density | 5.3-5.65 g/cm3 (hexahydrate)[4] |
| Melting point | decomposes[1] |
| very soluble | |
| Solubility | Insoluble in organic solvents[2] |
| Hazards | |
| GHS labelling:[1] | |
 
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| Danger | |
| H301, H311, H314, H331 | |
| P260, P262, P264, P264+P265, P270, P271, P280, P301+P316, P301+P330+P331, P302+P352, P302+P361+P354, P304+P340, P305+P354+P338, P316, P317, P321, P330, P361+P364, P363, P403+P233, P405, P501 | |
| Related compounds | |
Other anions
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Hexachloroplatinic acid |
Other cations
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Sodium hexachloroosmate, Potassium hexachloroosmate, Ammonium hexachloroosmate(IV) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Chloroosmic acid (also known as hexachloroosmic acid, and dihydrogen hexachloroosmate) is an inorganic chemical compound with the chemical formula H2OsCl6. It exists as a dark hygroscopic solid. It forms a hexahydrate.[5]
Synthesis
[edit]Hexachloroosmic acid can be prepared by reducing osmium tetroxide in hydrochloric acid with alcohol and heating.[3][6] Ferrous chloride is sometimes used in place of alcohol.[7]
- OsO4 + 4FeCl2 + 10HCl → H2OsCl6 + 4FeCl3 + 4H2O
Another way of preparing it is by dissolving osmium dioxide in hydrochloric acid.[8]
- OsO2 + 6HCl → H2OsCl6 + 2H2O[9]
It can also be prepared by reducing potassium osmate with hydrochloric acid under heating.[2]
Properties
[edit]Solid crystals of hexachloroosmic acid have been described as reddish-purple in color,[2] while commercial vendors describe it as black.[1][5] In solution, it exhibits colors ranging from yellowish green to reddish brown.[6][3][2] Owing to its highly hygroscopic nature, solutions of hexachloroosmic acid can be evaporated down to a syrup without crystallization.[3] As an acid, it is corrosive.
Reactions
[edit]When strong alkali is added to hexachloroosmic acid, it decomposes and precipitates osmium dioxide.[8][6]
It also reacts with alkali chlorides to yield hexachloroosmate salts, such as ammonium hexachloroosmate(IV).[3]
The coordination complex [H(DMSO)2]2(OsCl6) can be made by reacting chloroosmic acid in ethanol with dimethyl sulfoxide.[10]
References
[edit]- ^ a b c "Dihydrogen Hexachloroosmate(IV) Hydrate". American Elements. Retrieved 19 June 2025.
- ^ a b c d e f Chiririwa, Haleden; Muzenda, Edison (November 2014). "The Preparation and Characterisation of Osmium (IV), Osmium (II), and Osmium (0) Complexes from Refinery Materials" (PDF). International Conference on Chemical Engineering & Advanced Computational Technologies: 32–33. Retrieved 19 June 2025.
- ^ a b c d e Gilchrist, Raleigh (June 8, 1932). "A new determination of the atomic weight of Osmium" (PDF). Bureau of Standards Journal of Research. 9 (3): 279–290. doi:10.6028/jres.009.021. Retrieved 19 June 2025.
- ^ "Dihydrogen hexachloroosmate (IV) hexahydrate". Cymit Quimica. Retrieved 19 June 2025.
- ^ a b "Dihydrogen hexachloroosmate (IV) hexahydrate". Strem Catalog. Retrieved 19 June 2025.
- ^ a b c Gilchrist, Raleigh (1931). "A method for the separation and gravimetric determination of osmium" (PDF). J Res Bur Stand. 6 (3): 421–448. doi:10.6028/jres.006.028. Retrieved 19 June 2025.
- ^ Buckingham, D.A. (1961). Preparation and Oxidation-Reduction Potentials of Some Osmium Compounds (PhD thesis). Australian National University. p. 4.
- ^ a b Stopinski, Orin (September 1977). "Platinum-Group Metals" (PDF). Environmental Health Effects Research Series. Washington, DC: Environmental Protection Agency: 85–86. Retrieved 19 June 2025.
- ^ Sidgwick, N.V. (1950). The Elements and Their Compounds (PDF). Vol. 2. London: Oxford University Press. p. 1494. Retrieved 20 November 2025.
- ^ Rudnitskaya, O.V.; Kultyshkina, E.K.; Dobrokhotova, E.V.; Anan'ev I.V. (2014). "Synthesis and Structure of [H(DMSO)2]2[OsX6] (X=Cl, Br)". Russian Journal of Coordination Chemistry. 20: 911–912. Retrieved 21 November 2025.