Manganese trifluoride
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| Names | |
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IUPAC name
Manganese(III) fluoride
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| Other names
Manganese trifluoride, manganic fluoride
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| Identifiers | |
7783-53-1 
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| 3D model (Jmol) | Interactive image |
| ChemSpider |
74193
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| ECHA InfoCard | 100.029.096 |
| PubChem | 82213 |
| RTECS number | OP0882600 |
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| Properties | |
| MnF3 | |
| Molar mass | 111.938 g/mol |
| Appearance | purple-pink powder hygroscopic |
| Density | 3.54 g/cm3 |
| Melting point | > 600 °C (1,112 °F; 873 K) (decomposes) |
| hydrolysis | |
| +10,500·10−6 cm3/mol | |
| Structure | |
| Monoclinic, mS48 | |
| C2/c, No. 15 | |
| distorted octahedral | |
| Hazards | |
| Main hazards | toxic fumes |
| R-phrases | 8-20/21/22-36/37/38 |
| S-phrases | 17-26-36/37/39 |
| Related compounds | |
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Other anions
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manganese(III) oxide, manganese(III) acetate |
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Other cations
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chromium(III) fluoride, iron(III) fluoride. cobalt(III) fluoride |
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Related compounds
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manganese(II) fluoride, manganese(IV) fluoride |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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 (what is  ?) |
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| Infobox references | |
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 also forms a hydrate.
MnF3 can be prepared by treating a solution of MnF2 in hydrogen fluoride with fluorine:
It can also be prepared by the reaction of elemental fluorine with a manganese(II) halide at ~250 °C.
In the crystalline state, MnF3 resembles vanadium(III) fluoride: both feature octahedral metal centers with the same average M-F bond distances. In the Mn compound, however, is distorted (and hence a monoclinic 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 is unusual in that it forms two different structures (both based on [Mn(H2O)4F2]+ [Mn(H2O)2F4]− ), which have space groups P21/c and P21/a.
MnF3 reacts with sodium fluoride to give the octahedral hexafluorate anion:
Other reaction conditions give compounds with anion formula MnF52− or MnF4−. These anions are chain and layer structures respectively, with bridging fluorine. Manganese remains 6 coordinate, octahedral, and trivalent in all these materials.
Manganese(III) fluoride fluorinates organic compounds including aromatic hydrocarbons, cyclobutenes, and fullerenes.
On heating, MnF3 decomposes to manganese(II) fluoride.
Other manganese(III) compounds include manganese(III) acetate (CAS# 993-02-2), manganese acetylacetonate (CAS# 14284-89-0), Both are employed as oxidants in organic synthesis. MnF3 is Lewis acidic and forms a variety of derivatives. Two examples are K2MnF3(SO4) and K2MnF5.
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