Cobalt(III) fluoride

Cobalt(III) fluoride
Other names

Cobalt trifluoride
Cobaltic fluoride
Cobalt fluoride
Cobaltic trifluoride
Identifiers
CAS number 10026-18-3 Y
PubChem 66208
ChemSpider 59593 Y
Jmol-3D images Image 1
Properties
Molecular formula CoF3
Molar mass 115.9284 g/mol
Appearance brown solid
Density 3.88 g/cm3
Melting point

927 °C[1]
Solubility in water reacts
Hazards
NFPA 704
0
3
2
Related compounds
Other anions cobalt(III) oxide, cobalt(III) chloride
Other cations iron(III) fluoride, rhodium(III) fluoride
Related compounds cobalt(II) fluoride
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Cobalt(III) fluoride is the inorganic compound with the formula CoF3. This highly reactive, hygroscopic brown solid is used to synthesize organofluorine compounds.[2] CoF3 is a powerful fluorinating agent, the product being CoF2.

Contents

Preparation

CoF3 is prepared in the laboratory by treating CoCl2 with fluorine at 250 °C:[3]

CoCl2 + 3/2 F2 → CoF3 + Cl2

This conversion is a redox reaction: Co2+ is converted to Co3+ and chloride to chlorine at the expense of fluorine, which is converted to fluoride. Cobalt(II) oxide (CoO) and cobalt(II) fluoride (CoF2) can also be converted to cobalt(III) fluoride using fluorine.

Reactions

CoF3 decomposes upon contact with water to give oxygen:

4 CoF3 + 2 H2O → 4 HF + 4 CoF2 + O2

CoF3 is hygroscopic, forming a dihydrate (CAS#54496-71-8). It reacts with fluoride sources to give the anion [CoF6]3-, which is a rare example of a high-spin, octahedral cobalt(III) complex.

Applications

Used as slurry, CoF3 converts hydrocarbons to the perfluorocarbons:

2CoF3 + R-H → 2CoF2 + R-F + HF

Such reactions are sometimes accompanied by rearrangements or other reactions.[2] The related reagent KCoF4 is more selective.[4]

References

  1. ^ Lide, David R., ed (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3. 
  2. ^ a b Coe, P. L. "Cobalt(III) Fluoride" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.
  3. ^ Priest, H. F. “Anhydrous Metal Fluorides” Inorganic Syntheses McGraw-Hill: New York, 1950; Vol. 3, pages 171-183.
  4. ^ Coe, P. L. "Potassium Tetrafluorocobaltate(III)" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.

External links