Vanadium(III) fluoride

Vanadium(III) fluoride is the chemical compound with the formula VF3. This yellow-green, refractory solid is obtained in a two-step procedure from V2O3.[4] Similar to other transition-metal fluorides (such as MnF2), it exhibits magnetic ordering at low temperatures (e.g. V2F6.4H2O orders below 12 K[5]).

Vanadium(III) fluoride
Names
Other names
Vanadium fluoride, Vanadium trifluoride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.030.141
UNII
  • InChI=1S/3FH.V/h3*1H;/q;;;+3/p-3 checkY
    Key: PASVSMBJEYQYSN-UHFFFAOYSA-K checkY
  • InChI=1/3FH.V/h3*1H;/q;;;+3/p-3
    Key: PASVSMBJEYQYSN-DFZHHIFOAM
  • [V+3].[F-].[F-].[F-]
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]
a = 5.17 Å, c = 13.402 Å[2]
α = 90°, β = 90°, γ = 120°
Hazards
GHS labelling:
GHS05: CorrosiveGHS06: Toxic[3]
Danger
H301, H311, H314, H331[3]
P261, P280, P301+P310, P305+P351+P338, P310[3]
NFPA 704 (fire diamond)
NFPA 704 four-colored diamond
3
0
2
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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Infobox references

Preparation

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.

VF3 can also be prepared by treatment of V2O3 with HF. VF3 is a crystalline solid with 6 coordinate vanadium atoms with bridging fluorine atoms. The magnetic moment indicates the presence of two unpaired electrons.

References
  1. Lide, David R., ed. (2009). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. ISBN 978-1-4200-9084-0.
  2. Douglas, Bodie E.; Ho, Shih-Ming (2007). Structure and Chemistry of Crystalline Solids. New York: Springer Science+Business Media, Inc. p. 102. ISBN 978-0-387-26147-8.
  3. Sigma-Aldrich Co., Vanadium(III) fluoride. Retrieved on 2014-06-25.
  4. Sturm, B. J.; Sheridan, C. W. "Vanadium(III) Fluoride" Inorganic Syntheses 1963; Vol. 7, pages 52-54. ISBN 0-88275-165-4.
  5. S. Nakhal et al., Z. Kristallogr. 228, 347 (2013).doi:10.1524/zkri.2013.1664


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