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
SMILES F[Co](F)F
InChI InChI=1S/Co.3FH/h;3*1H/q+3;;;/p-3 Y Key: WZJQNLGQTOCWDS-UHFFFAOYSA-K Y InChI=1/Co.3FH/h;3*1H/q+3;;;/p-3 Key: WZJQNLGQTOCWDS-DFZHHIFOAL
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
Y (verify) (what is: Y/N?) 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.

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 flouride 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

• National Pollutant Inventory - Cobalt fact sheet
• National Pollutant Inventory - Fluoride and compounds fact sheet