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| Names | |
|---|---|
| IUPAC name Vanadium(III) bromide | |
| Other names Vanadium tribromide | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider |
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| ECHA InfoCard | 100.033.382 |
| EC Number |
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| RTECS number |
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| Properties | |
| VBr3 | |
| Molar mass | 290.654 g/mol |
| Appearance | Green-black solid |
| Density | 4 g/cm3 |
| soluble | |
| Solubility | soluble in THF (forms adduct) |
| +2890.0·10−6 cm3/mol | |
| Structure | |
| octahedral | |
| Hazards | |
| GHS labelling:[1] | |
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| Danger | |
| H314 | |
| P260,P264,P280,P301+P330+P331,P302+P361+P354,P304+P340,P305+P354+P338,P316,P321,P363,P405,P501 | |
| Related compounds | |
Otheranions | Vanadium(III) chloride |
Othercations | Titanium(III) bromide Molybdenum(III) bromide |
Related compounds | Vanadium(II) bromide |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Vanadium(III) bromide, also known as vanadium tribromide, describes theinorganic compounds with the formula VBr3 and its hydrates. The anhydrous material is a green-black solid. In terms of its structure, the compound ispolymeric with octahedral vanadium(III) surrounded by six bromide ligands.
VBr3 has been prepared by treatment ofvanadium tetrachloride withhydrogen bromide:
The reaction proceeds via the unstable vanadium(IV) bromide (VBr4), which releases Br2 near room temperature.[2]
It is also possible to prepare vanadium(III) bromide by reactingbromine with vanadium or ferrovanadine:[3]
Vanadium(III) bromide is present in the form of black, leafy, very hygroscopic crystals with a sometimes greenish sheen. It is soluble in water with green color. Its crystal structure is isotypic to that ofvanadium(III) chloride withspace group R3c (space group no. 167),a = 6.400 Å,c = 18.53 Å. When heated to temperatures of around 500 °C, a violet gas phase is formed, from which, under suitable conditions, red vanadium(IV) bromide can be separated by rapid cooling, which decomposes at −23 °C.[3]
Likevanadium(III) chloride, vanadium(III) bromide forms red-brown soluble complexes with dimethoxyethane andTHF, such asmer-VBr3(THF)3.[4]
Aqueous solutions prepared from VBr3 contain the cationtrans-[VBr2(H2O)4]+. Evaporation of these solutions give the salt trans-[VBr2(H2O)4]Br.(H2O)2.[5]
