Cobalt(III) fluoride

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Cobalt(III) fluoride
Cobalt(III) fluoride
Identifiers
CAS number 10026-18-3 YesY
PubChem 66208
ChemSpider 59593 YesY
EC number 233-062-4
Jmol-3D images Image 1
Properties
Molecular formula CoF3
Molar mass 115.928 g/mol
Appearance brown powder
Density 3.88 g/cm3
Melting point 927 °C (1,701 °F; 1,200 K)
Solubility in water reacts
Structure
Crystal structure hexagonal
Related compounds
Other anions cobalt(III) oxide, cobalt(III) chloride
Other cations iron(III) fluoride, rhodium(III) fluoride
Related compounds cobalt(II) fluoride
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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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.[1] CoF3 is a powerful fluorinating agent that leaves CoF2 as the byproduct.

Preparation[edit]

CoF3 is prepared in the laboratory by treating CoCl2 with fluorine at 250 °C:[2]

CoCl2 + 3/2 F2 → CoF3 + Cl2

This conversion is a redox reaction: Co2+ and Cl- are oxidized to Co3+ and Cl2, respectively, while F2 is reduced to F-. Cobalt(II) oxide (CoO) and cobalt(II) fluoride (CoF2) can also be converted to cobalt(III) fluoride using fluorine.

Reactions[edit]

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[edit]

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.[1] The related reagent KCoF4 is more selective.[3]

References[edit]

  1. ^ 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:10.1002/047084289X.rc185.
  2. ^ Priest, H. F. "Anhydrous Metal Fluorides" Inorganic Syntheses McGraw-Hill: New York, 1950; Vol. 3, pages 171-183. doi:10.1002/9780470132340.ch47
  3. ^ Coe, P. L. "Potassium Tetrafluorocobaltate(III)" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. doi:10.1002/047084289X.rp251.

External links[edit]