Manganese(III) fluoride (also known as Manganese trifluoride) is the
inorganic compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...
with the formula MnF
3. This red/purplish solid is useful for converting
hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ex ...
s into
fluorocarbon
Fluorocarbons are chemical compounds with carbon-fluorine bonds. Compounds that contain many C-F bonds often has distinctive properties, e.g., enhanced stability, volatility, and hydrophobicity. Fluorocarbons and their derivatives are commerci ...
s, i.e., it is a
fluorination
In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polymers, ...
agent.
It forms a hydrate and many derivatives.
Synthesis, structure and reactions
MnF
3 can be prepared by treating a solution of MnF
2 in
hydrogen fluoride
Hydrogen fluoride (fluorane) is an inorganic compound with the chemical formula . This colorless gas or liquid is the principal industrial source of fluorine, often as an aqueous solution called hydrofluoric acid. It is an important feedstock i ...
with
fluorine
Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reacti ...
:
:MnF
2 + 0.5 F
2 → MnF
3
It can also be prepared by the reaction of elemental fluorine with a manganese(II) halide at ~250 °C.
[Inorganic chemistry, Catherine E. Housecroft, A.G. Sharpe, pp.711-712, section ''Manganese (III)'' ]
googlebooks link
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Structure
Like vanadium(III) fluoride
Vanadium(III) fluoride is the chemical compound with the formula V F3. This yellow-green, refractory solid is obtained in a two-step procedure from V2O3.
Similar to other transition-metal fluorides (such as MnF2), it exhibits magnetic ordering a ...
, MnF3 features octahedral metal centers with the same average M-F bond distances. In the Mn compound, however, is distorted (and hence a monoclinic
In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic s ...
unit cell vs. a higher symmetry one) due to the Jahn-Teller effect, with pairs of Mn-F distances of 1.79, 1.91, 2.09 Å.
The hydrate MnF3.3H2O is obtained by crystallisation of MnF3 from hydrofluoric acid. The hydrate exists as two polymorphs, with space group
In mathematics, physics and chemistry, a space group is the symmetry group of an object in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of an object that leave it unchan ...
s P21/c and P21/a. Each consists of the salt 2O)4F2">n(H2O)4F2sup>+ 2O)2F4">n(H2O)2F4sup>− ).
Reactions
MnF3 is Lewis acidic and forms a variety of derivatives. One example is K2MnF3(SO4). MnF3 reacts with sodium fluoride
Sodium fluoride (NaF) is an inorganic compound with the formula . It is used in trace amounts in the fluoridation of drinking water, in toothpaste, in metallurgy, and as a flux. It is a colorless or white solid that is readily soluble in water. I ...
to give the octahedral hexafluoride:
:3NaF + MnF3 → Na3MnF6
Related reactions salts of the anions MnF52− or MnF4−. These anions adopt chain and layer structures respectively, with bridging fluoride. Manganese remains 6 coordinate, octahedral, and trivalent in all of these materials.
Manganese(III) fluoride fluorinates organic compounds including aromatic hydrocarbons, cyclobutenes, and fullerene
A fullerene is an allotrope of carbon whose molecule consists of carbon atoms connected by single and double bonds so as to form a closed or partially closed mesh, with fused rings of five to seven atoms. The molecule may be a hollow sphere, ...
s.
On heating, MnF3 decomposes to manganese(II) fluoride
Manganese(II) fluoride is the chemical compound composed of manganese and fluoride with the formula MnF2. It is a light pink solid, the light pink color being characteristic for manganese(II) compounds. It is made by treating manganese and diverse ...
.
MnF3 is a source of MnCl3 complexes by reaction with bismuth trichloride.
See also
* CoF3, another fluorinating agent based on a transition metal in an oxidising +3 state.
References
Further reading
Novel syntheses of some binary fluorides: the role of anhydrous hydrogen fluoride
Acta Chim. Slov. 1999, 46(2), pp. 229–238, Zoran Mazej, Karel Lutar and Boris Žemva
*Knudsen Cell mass spectrometry study of Manganese Trifluoride vaporisation, High temperature corrosion and materials chemistry IV: proceedings of the International Symposium, pp. 521–525,
google books
External links
* ttps://web.archive.org/web/20060301151751/http://www.npi.gov.au/database/substance-info/profiles/52.html National Pollutant Inventory: Manganese and compounds Fact Sheet
{{DEFAULTSORT:Manganese(Iii) Fluoride
Fluorides
Manganese(III) compounds
Metal halides
Fluorinating agents