Chromium pentafluoride
Chemical compound
From Wikipedia, the free encyclopedia
Chromium pentafluoride is the inorganic compound with the chemical formula CrF5.[3] It is a red volatile solid that melts at 34 °C.[1] It is the highest known chromium fluoride, since the hypothetical chromium hexafluoride has not yet been synthesized.[4]
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| Names | |
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| IUPAC name
Chromium(V) fluoride | |
Other names
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| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties[1] | |
| CrF5 | |
| Molar mass | 146.988 g/mol |
| Appearance | red crystals |
| Density | 2.89 g/cm3 |
| Melting point | 34 °C (93 °F; 307 K) |
| Boiling point | 117 °C (243 °F; 390 K) |
| Structure[2] | |
| orthorhombic | |
| Pbcm, No. 57 | |
a = 782.9 pm, b = 753.4 pm, c = 551.8 pm | |
Formula units (Z) |
4 |
| octahedral | |
| Related compounds | |
Related compounds |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Chromium pentafluoride is one of the products of the action of fluorine on a mixture of potassium and chromic chlorides.[5]
In terms of its structure, the compound is a one-dimensional coordination polymer. Each Cr(V) center has octahedral molecular geometry.[2] It has the same crystal structure as vanadium pentafluoride.[6]
Chromium pentafluoride is strongly oxidizing, able to fluorinate the noble gas xenon and oxidize dioxygen to dioxygenyl.[2] Due to this property, it decomposes readily in the presence of reducing agents, and easily hydrolyses to chromium(III) and chromium(VI).[7]
Reactions
Chromium pentafluoride can react with Lewis bases such as caesium fluoride and nitryl fluoride to give the respective hexafluorochromate(V) salt.[8]
- CrF5 + CsF → CsCrF6
Chromium pentafluoride can also react with the Lewis acid antimony pentafluoride to give the CrF5·2SbF5 adduct. The adduct was found to be a strong oxidizing agent, liquid at room temperature with a melting point of −23 °C.[8]