Cobalt(III) fluoride

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Cobalt(III) fluoride
Aluminium-trifluoride-3D-polyhedra.png
Cobalt(III) fluoride.png
Names
Other names
Cobalt trifluoride
Cobaltic fluoride
Cobalt fluoride
Cobaltic trifluoride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.030.045 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 233-062-4
PubChem CID
UNII
  • InChI=1S/Co.3FH/h;3*1H/q+3;;;/p-3 Yes check.svgY
    Key: WZJQNLGQTOCWDS-UHFFFAOYSA-K Yes check.svgY
  • InChI=1/Co.3FH/h;3*1H/q+3;;;/p-3
    Key: WZJQNLGQTOCWDS-DFZHHIFOAL
  • F[Co](F)F
Properties
CoF3
Molar mass 115.928 g/mol
Appearancebrown powder
Density 3.88 g/cm3
Melting point 927 °C (1,701 °F; 1,200 K)
reacts
+1900.0·10−6 cm3/mol
Structure
hexagonal
Hazards
NFPA 704 (fire diamond)
NFPA 704.svgHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazards (white): no code
3
0
2
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 otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Cobalt(III) fluoride is the inorganic compound with the formula CoF3. Hydrates are also known. The anhydrous compound is a hygroscopic brown solid. It is used to synthesize organofluorine compounds. [1]

Contents

The related cobalt(III) chloride is also known but is extremely unstable. [2] Cobalt(III) bromide and cobalt(III) iodide have not been synthesized.

Structure

Anhydrous

Anhydrous cobalt trifluoride crystallizes in the rhombohedral group, specifically according to the aluminium trifluoride motif, with a = 527.9 pm, α = 56.97°. Each cobalt atom is bound to six fluorine atoms in octahedral geometry, with Co–F distances of 189 pm. Each fluoride is a doubly bridging ligand. [3]

Hydrates

A hydrate CoF3·3.5H2O is known. It is conjectured to be better described as [CoF3(H2O)3]·0.5H2O. [3]

There is a report of an hydrate CoF3·3.5H2O, isomorphic to AlF3·3H2O. [3]

Preparation

Cobalt trifluoride can be prepared in the laboratory by treating CoCl2 with fluorine at 250 °C: [4] [3]

CoCl2 + 3/2 F2 → CoF3 + Cl2

In this 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. [3]

The compound can also be formed by treating CoCl2 with chlorine trifluoride ClF3 or bromine trifluoride BrF3. [3]

Reactions

CoF3 decomposes upon contact with water to give oxygen:

4 CoF3 + 2 H2O → 4 HF + 4 CoF2 + O2

It reacts with fluoride salts to give the anion [CoF6]3−, which is also features high-spin, octahedral cobalt(III) center.

Applications

CoF3 is a powerful fluorinating agent. Used as slurry, CoF3 converts hydrocarbons to the perfluorocarbons:

2 CoF3 + R-H → 2 CoF2 + R-F + HF

CoF2 is the byproduct.

Such reactions are sometimes accompanied by rearrangements or other reactions. [1] The related reagent KCoF4 is more selective. [5]

Gaseous CoF3

In the gas phase, CoF3 is calculated to be planar in its ground state, and has a 3-fold rotation axis (point group D3h). The Co3+ ion has a ground state of 3d65D. The fluoride ligands split this state into, in energy order, 5A', 5E", and 5E' states. The first energy difference is small and the 5E" state is subject to the Jahn-Teller effect, so this effect needs to be considered to be sure of the ground state. The energy lowering is small and does not change the energy order. [6] This calculation was the first treatment of the Jahn-Teller effect using calculated energy surfaces.

Related Research Articles

Iron(III) chloride describes the inorganic compounds with the formula FeCl3(H2O)x. Also called ferric chloride, these compounds are some of the most important and commonplace compounds of iron. They are available both in anhydrous and in hydrated forms which are both hygroscopic. They feature iron in its +3 oxidation state. The anhydrous derivative is a Lewis acid, while all forms are mild oxidizing agents. It is used as a water cleaner and as an etchant for metals.

<span class="mw-page-title-main">Copper(II) nitrate</span> Chemical compound

Copper(II) nitrate describes any member of the family of inorganic compounds with the formula Cu(NO3)2(H2O)x. The hydrates are blue solids. Anhydrous copper nitrate forms blue-green crystals and sublimes in a vacuum at 150-200 °C. Common hydrates are the hemipentahydrate and trihydrate.

<span class="mw-page-title-main">Chromium(III) chloride</span> Chemical compound

Chromium(III) chloride (also called chromic chloride) is an inorganic chemical compound with the chemical formula CrCl3. It forms several hydrates with the formula CrCl3·nH2O, among which are hydrates where n can be 5 (chromium(III) chloride pentahydrate CrCl3·5H2O) or 6 (chromium(III) chloride hexahydrate CrCl3·6H2O). The anhydrous compound with the formula CrCl3 are violet crystals, while the most common form of the chromium(III) chloride are the dark green crystals of hexahydrate, CrCl3·6H2O. Chromium chlorides find use as catalysts and as precursors to dyes for wool.

Boron trifluoride is the inorganic compound with the formula BF3. This pungent, colourless, and toxic gas forms white fumes in moist air. It is a useful Lewis acid and a versatile building block for other boron compounds.

<span class="mw-page-title-main">Manganese(III) fluoride</span> Chemical compound

Manganese(III) fluoride (also known as Manganese trifluoride) is the inorganic compound with the formula MnF3. This red/purplish solid is useful for converting hydrocarbons into fluorocarbons, i.e., it is a fluorination agent. It forms a hydrate and many derivatives.

<span class="mw-page-title-main">Nickel(II) fluoride</span> Chemical compound

Nickel(II) fluoride is the chemical compound with the formula NiF2. It is an ionic compound of nickel and fluorine and forms yellowish to green tetragonal crystals. Unlike many fluorides, NiF2 is stable in air.

<span class="mw-page-title-main">Bromine trifluoride</span> Chemical compound

Bromine trifluoride is an interhalogen compound with the formula BrF3. At room temperature, it is a straw-coloured liquid with a pungent odor which decomposes violently on contact with water and organic compounds. It is a powerful fluorinating agent and an ionizing inorganic solvent. It is used to produce uranium hexafluoride (UF6) in the processing and reprocessing of nuclear fuel.

<span class="mw-page-title-main">Chromium(III) fluoride</span> Chemical compound

Chromium(III) fluoride is an inorganic compound with the chemical formula CrF3. It forms several hydrates. The compound CrF3 is a green crystalline solid that is insoluble in common solvents, but the hydrates [Cr(H2O)6]F3 (violet) and [Cr(H2O)6]F3·3H2O (green) are soluble in water. The anhydrous form sublimes at 1100–1200 °C.

<span class="mw-page-title-main">Iron(II) fluoride</span> Chemical compound

Iron(II) fluoride or ferrous fluoride is an inorganic compound with the molecular formula FeF2. It forms a tetrahydrate FeF2·4H2O that is often referred to by the same names. The anhydrous and hydrated forms are white crystalline solids.

<span class="mw-page-title-main">Cobalt(II) fluoride</span> Chemical compound

Cobalt(II) fluoride is a chemical compound with the formula (CoF2). It is a pink crystalline solid compound which is antiferromagnetic at low temperatures (TN=37.7 K) The formula is given for both the red tetragonal crystal, (CoF2), and the tetrahydrate red orthogonal crystal, (CoF2·4H2O). CoF2 is used in oxygen-sensitive fields, namely metal production. In low concentrations, it has public health uses. CoF2 is sparingly soluble in water. The compound can be dissolved in warm mineral acid, and will decompose in boiling water. Yet the hydrate is water-soluble, especially the di-hydrate CoF2·2H2O and tri-hydrate CoF2·3H2O forms of the compound. The hydrate will also decompose with heat.

<span class="mw-page-title-main">Iron(III) fluoride</span> Chemical compound

Iron(III) fluoride, also known as ferric fluoride, are inorganic compounds with the formula FeF3(H2O)x where x = 0 or 3. They are mainly of interest by researchers, unlike the related iron(III) chloride. Anhydrous iron(III) fluoride is white, whereas the hydrated forms are light pink.

Antimony pentafluoride is the inorganic compound with the formula SbF5. This colourless, viscous liquid is a strong Lewis acid and a component of the superacid fluoroantimonic acid, formed upon mixing liquid HF with liquid SbF5 in 1:1 ratio. It is notable for its strong Lewis acidity and the ability to react with almost all known compounds.

<span class="mw-page-title-main">Chromium(II) chloride</span> Chemical compound

Chromium(II) chloride describes inorganic compounds with the formula CrCl2(H2O)n. The anhydrous solid is white when pure, however commercial samples are often grey or green; it is hygroscopic and readily dissolves in water to give bright blue air-sensitive solutions of the tetrahydrate Cr(H2O)4Cl2. Chromium(II) chloride has no commercial uses but is used on a laboratory-scale for the synthesis of other chromium complexes.

<span class="mw-page-title-main">Hexafluorosilicic acid</span> Octahedric silicon compound

Hexafluorosilicic acid is an inorganic compound with the chemical formula H
2SiF
6. Aqueous solutions of hexafluorosilicic acid consist of salts of the cation and hexafluorosilicate anion. These salts and their aqueous solutions are colorless.

<span class="mw-page-title-main">Sulfur tetrafluoride</span> Chemical compound

Sulfur tetrafluoride is the chemical compound with the formula SF4. It is a colorless corrosive gas that releases dangerous HF upon exposure to water or moisture. Despite these unwelcome characteristics, this compound is a useful reagent for the preparation of organofluorine compounds, some of which are important in the pharmaceutical and specialty chemical industries.

<span class="mw-page-title-main">Zinc fluoride</span> Chemical compound

Zinc fluoride is an inorganic chemical compound with the chemical formula ZnF2. It is encountered as the anhydrous form and also as the tetrahydrate, ZnF2·4H2O (rhombohedral crystal structure). It has a high melting point and has the rutile structure containing 6 coordinate zinc, which suggests appreciable ionic character in its chemical bonding. Unlike the other zinc halides, ZnCl2, ZnBr2 and ZnI2, it is not very soluble in water.

<span class="mw-page-title-main">Selenium tetrafluoride</span> Chemical compound

Selenium tetrafluoride (SeF4) is an inorganic compound. It is a colourless liquid that reacts readily with water. It can be used as a fluorinating reagent in organic syntheses (fluorination of alcohols, carboxylic acids or carbonyl compounds) and has advantages over sulfur tetrafluoride in that milder conditions can be employed and it is a liquid rather than a gas.

<span class="mw-page-title-main">Antimony trifluoride</span> Chemical compound

Antimony trifluoride is the inorganic compound with the formula SbF3. Sometimes called Swarts' reagent, it is one of two principal fluorides of antimony, the other being SbF5. It appears as a white solid. As well as some industrial applications, it is used as a reagent in inorganic and organofluorine chemistry.

<span class="mw-page-title-main">Rhodium trifluoride</span> Chemical compound

Rhodium(III) fluoride or rhodium trifluoride is the inorganic compound with the formula RhF3. It is a red-brown, diamagnetic solid.

Cobalt compounds are chemical compounds formed by cobalt with other elements.

References

  1. 1 2 Coe, P. L. (2004). "Cobalt(III) Fluoride". Encyclopedia of Reagents for Organic Synthesis. J. Wiley. doi:10.1002/047084289X.rc185. ISBN   0471936235.
  2. ↑ Arthur W. Chester, El-Ahmadi Heiba, Ralph M. Dessau, and William J. Koehl Jr. (1969): "The interaction of cobalt(III) with chloride ion in acetic acid". Inorganic and Nuclear Chemistry Letters, volume 5, issue 4, pages 277-283. doi : 10.1016/0020-1650(69)80198-4
  3. 1 2 3 4 5 6 W. Levason and C. A. McAuliffe (1974): "Higher oxidation state chemistry of iron, cobalt, and nickel". Coordination Chemistry Reviews, volume 12, issue 2, pages 151-184. doi : 10.1016/S0010-8545(00)82026-3
  4. ↑ H. F. Priest (1950): "Anhydrous Metal Fluorides". In Inorganic Syntheses, McGraw-Hill, volume 3, pages 171-183. doi : 10.1002/9780470132340.ch47
  5. ↑ 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.
  6. ↑ Yates, J. H.; Pitzer, R. M. (1979). "Molecular and Electronic Structure of Transition Metal Trifluorides". J. Chem. Phys. 70 (9): 4049–4055. Bibcode:1979JChPh..70.4049Y. doi:10.1063/1.438027.
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