Vanadium(III) fluoride
Chemical compound
From Wikipedia, the free encyclopedia
Vanadium(III) fluoride is the chemical compound with the formula VF3. It is a yellow-green crystalline solid with hexacoordinate vanadium atoms and bridging fluorine atoms. The magnetic moment indicates the presence of two unpaired electrons. Similar to other transition-metal fluorides (such as MnF2), it exhibits magnetic ordering at low temperatures (e.g. V2F6.4H2O orders below 12 K[4]).
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| Names | |
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| Other names
Vanadium fluoride, Vanadium trifluoride | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.030.141 |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| F3V | |
| Molar mass | 107.9367 g·mol−1 |
| Appearance | Yellow-green powder (anhydrous) Green powder (trihydrate)[1] |
| Density | 3.363 g/cm3[1] |
| Melting point | 1,395 °C (2,543 °F; 1,668 K) at 760 mmHg (anhydrous) ~ 100 °C (212 °F; 373 K) at 760 mmHg (trihydrate) decomposes[1] |
| Boiling point | Sublimes |
| Insoluble[1] | |
| Solubility | Insoluble in EtOH[1] |
| 2.757·10−3 cm3/mol[1] | |
| Structure | |
| Rhombohedral, hR24[2] | |
| R3c, No. 167[2] | |
| 3 2/m[2] | |
α = 90°, β = 90°, γ = 120° | |
| Hazards | |
| GHS labelling: | |
  [3] | |
| Danger | |
| H301, H311, H314, H331[3] | |
| P261, P280, P301+P310, P305+P351+P338, P310[3] | |
| NFPA 704 (fire diamond) | |
| Related compounds | |
Other anions |
Vanadium(III) chloride Vanadium(III) oxide Vanadium(III) nitride |
Other cations |
Vanadium(IV) fluoride |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation
Vanadium(III) fluoride is obtained in a two-step procedure from V2O3.[5]
The first step entails conversion to the hexafluorovanadate(III) salt using ammonium bifluoride:
- V2O3 + 6 (NH4)HF2 → 2 (NH4)3VF6 + 3 H2O
In the second step, the hexafluorovanadate is thermally decomposed.
- (NH4)3VF6 → 3 NH3 + 3 HF + VF3
The thermal decomposition of ammonium salts is a relatively common method for the preparation of inorganic solids.
It can also be prepared by treatment of V2O3 with HF.[citation needed]