Manganese(III) fluoride

Synthesis, structure and reactions

MnF3 can be prepared by treating a solution of MnF2 in hydrogen fluoride with fluorine:{{cite journal :MnF2 + 0.5 F2 → MnF3

It can also be prepared by the reaction of elemental fluorine with a manganese(II) halide at ~250 °C.

Structure

Like vanadium(III) fluoride, MnF3 features 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.{{cite journal

The hydrate MnF3.3H2O is obtained by crystallisation of MnF3 from hydrofluoric acid. The hydrate exists as two polymorphs, with space groups P21/c and P21/a. Each consists of the salt [Mn(H2O)4F2]+[Mn(H2O)2F4]− ).

Reactions

MnF3 is Lewis acidic and forms a variety of derivatives. One example is K2MnF3(SO4). MnF3 reacts with sodium fluoride 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 fullerenes.

On heating, MnF3 decomposes to manganese(II) fluoride.

MnF3 is a source of MnCl3 complexes by reaction with bismuth trichloride.

References

References

1. GHS: [https://www.sigmaaldrich.com/catalog/product/ALDRICH/339296 sigma-aldrich 339296] {{Dead link. (December 2021)
2. (2004). "Manganese(III) Fluoride". J. Wiley & Sons.
3. Inorganic chemistry, Catherine E. Housecroft, A.G. Sharpe, pp.711-712, section ''Manganese (III)'', [https://books.google.com/books?id=3sy4ZAP4EGAC googlebooks link]
4. Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. {{ISBN. 0-19-855370-6.
5. (1957). "Interatomic Bonding in Manganese Trifluoride". [[Nature (journal).
6. (1992). "Structures of two polymorphs of MnF3·3H2O". Journal of Fluorine Chemistry.
7. (2007). "Inorganic Syntheses". [[Inorg. Synth.]].
8. [http://notes.fluorine1.ru/contents/Nov98/Notes/letters/letter1.html Fluorination of p-chlorobenzotrifluoride by manganese trifluoride] {{webarchive. link. (2011-08-23 A. Kachanov, V. Kornilov, V.Belogay, Fluorine Notes :Vol. 1 (1) November–December 1998, via ''notes.fluorine1.ru'')
9. Junji Mizukado. (2006). "Fluorination of Fluoro-Cyclobutene with High-Valency Metal Fluoride". Journal of Fluorine Chemistry.
10. V. É. Aleshina. (2002). "Fluorination of the Cubic and Hexagonal C₆₀ Modifications by Crystalline Manganese Trifluoride". Physics of the Solid State.
11. {{cite EB1911
12. In situ time-resolved X-ray diffraction study of manganese trifluoride thermal decomposition, J.V. Raua, V. Rossi Albertinib, N.S. Chilingarova, S. Colonnab, U. Anselmi Tamburini, Journal of Fluorine Chemistry 4506 (2001) 1–4, [http://ftp.esrf.eu/pub/UserReports/21876_A.pdf online version] {{Webarchive. link. (2017-12-30)
13. (2015). "Solvates of Manganese Trichloride Revisited - Synthesis, Isolation, and Crystal Structure of MnCl3(THF)3". Zeitschrift für Anorganische und Allgemeine Chemie.