Manganese(III) fluoride
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221110917
2008-06-23T02:36:10Z
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{{Chembox new
| Name = Manganese(III) fluoride
| ImageFile = Manganese(III) fluoride.jpg
| ImageSize = 200px
| ImageName = Manganese(III) fluoride
| IUPACName = Manganese(III) fluoride
| OtherNames = Manganese trifluoride
| Section1 = {{Chembox Identifiers
| CASNo = 7783-53-1
| RTECS = OP0882600
}}
| Section2 = {{Chembox Properties
| Formula = F<sub>3</sub>Mn
| MolarMass = 111.938 g/mol
| Appearance = purple-pink powder
| Density = 3.54 g/cm³, solid
| Solubility = hydrolysis
| MeltingPt = °C (? K)
}}
| Section3 = {{Chembox Structure
| Coordination = distorted octahedral
| CrystalStruct = [[Vanadium(III) fluoride|VF<sub>3</sub>]]
}}
| Section7 = {{Chembox Hazards
| MainHazards = toxic fumes
| RPhrases = 8-20/21/22-36/37/38
| SPhrases = 17-26-36/37/39
}}
| Section8 = {{Chembox Related
| OtherCpds = Manganese acetylacetonate<br />[[Cobalt(III) fluoride]]
}}
}}
'''Manganese trifluoride''' is the [[chemical compound]] with the formula MnF<sub>3</sub>. This purplish solid is highly reactive, being unstable in moist air and liberating F<sub>2</sub> upon heating. MnF<sub>3</sub> is useful for converting [[hydrocarbon]]s into [[fluorocarbon]]s; i.e., it is a fluorination agent.<ref>Burley, G. A.; Taylor, R. "Manganese(III) fluoride" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.</ref>
:R<sub>3</sub>C-H + 2 MnF<sub>3</sub> → R<sub>3</sub>C-F + HF + 2MnF<sub>2</sub>
A related fluorinating [[reagent]] is [[Cobalt(III) fluoride|CoF<sub>3</sub>]].
==Synthesis and reactions==
MnF<sub>3</sub> can be prepared by treating a solution of MnF<sub>2</sub> in anhydrous [[hydrogen fluoride]] with [[fluorine]]:<ref>{{cite journal
| title = Room temperature syntheses of MnF<sub>3</sub>, MnF<sub>4</sub> and hexafluoromanganete(IV) salts of alkali cations
| author = Z. Mazej
| journal = Journal of Fluorine Chemistry
| year = 2002
| volume = 114
| issue = 1
| pages = 75–80
| doi = 10.1016/S0022-1139(01)00566-8
}}</ref>
:MnF<sub>2</sub> + 0.5 F<sub>2</sub> → MnF<sub>3</sub>
In the crystalline state, MnF<sub>3</sub> resembles [[vanadium(III) fluoride]]: both feature octahedal 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 A.<ref>Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.</ref><ref>Hepworth, M. A.; Jack, K. H.; [[Ronald Sydney Nyholm|Nyholm]], R. S. ”Interatomic Bonding in Manganese Trifluoride” Nature 1957, 179, 211 - 212. doi:10.1038/179211b0</ref><ref>{{cite journal
| title = The crystal structure of manganese trifluoride, MnF<sub>3</sub>
| author = M. A. Hepworth, K. H. Jack
| journal = Acta Crystallographica
| year = 1957
| volume = 10
| issue =
| pages = 345–351
| doi = 10.1107/S0365110X57001024}}
</ref> Jahn-Teller distortions are characteristic of the presence of four d-electrons in the valence shell.
==Related Mn(III) and Mn(IV) compounds==
The fluorination of MnF<sub>2</sub> in HF, if conducted in the presence of UV-irradiation, gives MnF<sub>4</sub>. This tetrafluoride is a relatively rare Mn(IV) species, the most famous example being [[manganese dioxide]].
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]]. MnF<sub>3</sub> is Lewis acidic and forms a variety of derivatives. Two examples are K<sub>2</sub>MnF<sub>3</sub>(SO<sub>4</sub>)<ref>Bhattacharjee, M. N; Chaudhuri, M. K. “Dipotassium Trifluorosulfatomanganate(III)” Inorganic Syntheses, 1990, volume 27, pages 312-313. ISBN 0-471-50976-0</ref> and K<sub>2</sub>MnF<sub>5</sub>.
==Safety considerations==
Like other reactive inorganic fluorides, MnF<sub>3</sub> should be stored in a polyethylene bottle.
==References==
<references/>
==External links==
*[http://www.npi.gov.au/database/substance-info/profiles/44.html National Pollutant Inventory: Fluoride and compounds fact sheet]
*[http://www.npi.gov.au/database/substance-info/profiles/52.html National Pollutant Inventory: Manganese and compounds Fact Sheet]
[[Category:Fluorides]]
[[Category:Manganese compounds]]
[[Category:Metal halides]]
{{inorganic-compound-stub}}
[[ar:فلوريد منغنيز ثلاثي]]
[[pl:Fluorek manganu(III)]]