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Chloroosmic acid

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Chloroosmic acid
Solution of chloroosmic acid
Names
IUPAC name
Dihydrogen hexachloroosmate(2-)
Other names
  • Hexachloroosmic acid
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.043.797 Edit this at Wikidata
EC Number
  • 248-192-7
  • InChI=1S/6ClH.Os/h6*1H;/q;;;;;;+4/p-4
    Key: UTIXXJBEMJZGFB-UHFFFAOYSA-J
  • [H+].[H+].Cl[Os-2](Cl)(Cl)(Cl)(Cl)Cl
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]
GHS05: CorrosiveGHS06: Toxic
Danger
H301, H311, H314, H331
P260, P261, 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
Hexachloroplatinic acid
Other cations
Sodium hexachloroosmate,
Ammonium hexachloroosmate(IV)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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]

Another way of preparing it is by dissolving osmium dioxide in hydrochloric acid.[7]

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.[7][6]

It also reacts with alkali chlorides to yield hexachloroosmate salts, such as ammonium hexachloroosmate(IV).[3]

References

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  1. ^ a b c "Dihydrogen Hexachloroosmate(IV) Hydrate". American Elements. Retrieved 19 June 2025.
  2. ^ 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 (ICCEACT): 32–33. Retrieved 19 June 2025.
  3. ^ 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.
  4. ^ "Dihydrogen hexachloroosmate (IV) hexahydrate". Cymit Quimica. Retrieved 19 June 2025.
  5. ^ a b "Dihydrogen hexachloroosmate (IV) hexahydrate". Strem Catalog. Retrieved 19 June 2025.
  6. ^ 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.
  7. ^ 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.