Difference between revisions of "Manganese tetrafluoride"
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| Section2 = {{Chembox Properties | | Section2 = {{Chembox Properties | ||
| − | | Reference = | + | | Reference = <ref name="Hoppe">{{citation | title = Mangantetrafluorid, MnF<sub>4</sub> | first1 = Rudolf | last1 = Hoppe | first2 = Wolfgang | last2 = Dähne | first3 = Wilhelm | last3 = Klemm | journal = Naturwissenschaften | year = 1961 | volume = 48 | issue = 11 | page = 429 | doi = 10.1007/BF00621676}}.</ref><ref name="AstorPrepn">{{citation | inventor1-last = Torisu | inventor1-first = Junichi | inventor2-last = Oka | inventor2-first = Masakazu | inventor3-last = Kuznetsov | inventor3-first = Andrey Sergeyevich | inventor4-last = Petrov | inventor4-first = Yury Alexeyevich | assignee = Astor Electronics/Showa Denko | title = Method of manufacturing manganese tetrafluoride | country-code = WO | description = PCT Appl. | publication-number = 2006033480 | publication-date = 2006-03-30}}.</ref> |
| Formula = MnF<sub>4</sub> | | Formula = MnF<sub>4</sub> | ||
| MolarMass = 130.93 g mol<sup>−1</sup> | | MolarMass = 130.93 g mol<sup>−1</sup> | ||
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| − | '''Manganese tetrafluoride''', MnF<sub>4</sub>, is the highest [[fluoride]] of [[manganese]]. It is used as a powerful [[oxidizing agent]] and as a means of purifying elemental [[fluorine]].<ref name="AstorPrepn" | + | '''Manganese tetrafluoride''', MnF<sub>4</sub>, is the highest [[fluoride]] of [[manganese]]. It is used as a powerful [[oxidizing agent]] and as a means of purifying elemental [[fluorine]].<ref name="AstorPrepn"/><ref>{{citation | inventor1-last = Seseke-Koyro | inventor1-first = Ulrich | inventor2-last = Garcia-Juan | inventor2-first = Placido | inventor3-last = Palsherm | inventor3-first = Stefan | inventor4-last = Schulz | inventor4-first = Alf | assignee = Solvay Fluor | title = Process for the purification of elemental fluorine | country-code = WO | description = PCT Appl. | publication-number = 2009074562 | publication-date = 2009-06-18}}.</ref> |
==Preparation== | ==Preparation== | ||
| − | Manganese tetrafluoride was first unequivocally prepared in 1961{{#tag:ref|Reports of the preparation of MnF<sub>4</sub> date back to the nineteenth century,<ref>{{citation | first = W. H. | last = Melville | title = Contribution towards the History of the Fluorides of Manganese | journal = Proc. Am. Acad. Arts Sci. | volume = 12 | year = 1876 | pages = 228–34 | url = http://www.jstor.org/stable/25138452}}.</ref> but are inconsistent with the now-known chemistry of the genuine compound.|group=Note}} by the reaction of [[manganese(II) fluoride]] (or other Mn<sup>II</sup> compounds) with a stream of [[fluorine]] gas at 550 °C: the MnF<sub>4</sub> sublimes into the gas stream and condenses onto a [[cold finger]].<ref name="Hoppe" | + | Manganese tetrafluoride was first unequivocally prepared in 1961{{#tag:ref|Reports of the preparation of MnF<sub>4</sub> date back to the nineteenth century,<ref>{{citation | first = W. H. | last = Melville | title = Contribution towards the History of the Fluorides of Manganese | journal = Proc. Am. Acad. Arts Sci. | volume = 12 | year = 1876 | pages = 228–34 | url = http://www.jstor.org/stable/25138452}}.</ref> but are inconsistent with the now-known chemistry of the genuine compound.|group=Note}} by the reaction of [[manganese(II) fluoride]] (or other Mn<sup>II</sup> compounds) with a stream of [[fluorine]] gas at 550 °C: the MnF<sub>4</sub> sublimes into the gas stream and condenses onto a [[cold finger]].<ref name="Hoppe"/><ref>{{citation | first1 = Rudolf | last1 = Hoppe | first2 = Wolfgang | last2 = Dähne | first3 = Wilhelm | last3 = Klemm | title = Mangantetrafluorid mit einem Anhang über LiMnF<sub>5</sub> und LiMnF<sub>4</sub> | journal = Justus Liebigs Ann. Chem. | volume = 658 | issue = 1 | pages = 1–5 | year = 1962 | doi = 10.1002/jlac.19626580102}}.</ref> This is still the commonest method of preparation, although the sublimation can be avoided by operating at increased fluorine pressure (4.5–6 bar at 180–320 °C) and mechanically agitating the powder to avoid sintering of the grains.<ref name="AstorPrepn"/><ref name="SolvayPrepn">{{citation | inventor1-last = Seseke-Koyro | inventor1-first = Ulrich | inventor2-last = Garcia-Juan | inventor2-first = Placido | inventor3-last = Palsherm | inventor3-first = Stefan | inventor4-last = Schulz | inventor4-first = Alf | assignee = Solvay Fluor | title = Method for preparing manganese tetrafluoride | country-code = WO | description = PCT Appl. | publication-number = 2009074560 | publication-date = 2009-06-18}}.</ref> The reaction can also be carried out starting from [[manganese]] powder in a [[fluidized bed]].<ref>{{citation | first1 = H. | last1 = Roesky | first2 = O. | last2 = Glemser | title = A New Preparation of Manganese Tetrafluoride | journal = Angew. Chem., Int. Ed. Engl. | volume = 2 | issue = 10 | page = 626 | year = 1963 | doi = 10.1002/anie.196306262}}.</ref><ref>{{citation | first1 = Herbert W. | last1 = Roesky | first2 = Oskar | last2 = Glemser | first3 = Karl-Heinz | last3 = Hellberg | title = Darstellung von Metallfluoriden in der Wirbelschicht | journal = Chem. Ber. | volume = 98 | issue = 6 | pages = 2046–48 | year = 1965 | doi = 10.1002/cber.19650980642}}.</ref> |
Other preparations of MnF<sub>4</sub> include the fluorination of MnF<sub>2</sub> with [[krypton difluoride]],<ref>{{citation | first1 = Karel | last1 = Lutar | first2 = Adolf | last2 = Jesih | first3 = Boris | last3 = Žemva | title = KrF<sub>2</sub>/MnF<sub>4</sub> adducts from KrF<sub>2</sub>/MnF<sub>2</sub> interaction in HF as a route to high purity MnF<sub>4</sub> | journal = Polyhedron | volume = 7 | issue = 13 | year = 1988 | pages = 1217–19 | doi = 10.1016/S0277-5387(00)81212-7}}.</ref> or with F<sub>2</sub> in liquid [[hydrogen fluoride]] solution under [[ultraviolet light]].<ref name="Mazej">{{citation | first = Z. | last = Mazej | title = Room temperature syntheses of MnF<sub>3</sub>, MnF<sub>4</sub> and hexafluoromanganete(IV) salts of alkali cations | journal = J. Fluorine Chem. | volume = 114 | issue = 1 | year = 2002 | pages = 75–80 | doi = 10.1016/S0022-1139(01)00566-8}}.</ref> Manganese tetrafluoride has also been prepared (but not isolated) in an acid–base reaction between [[antimony pentafluoride]] and K<sub>2</sub>MnF<sub>6</sub> as part of a chemical synthesis of elemental fluorine.<ref name="Christe">{{citation | first = Karl O. | last = Christe | year = 1986 | title = Chemical synthesis of elemental fluorine | journal = Inorg. Chem. | volume = 25 | issue = 21 | pages = 3721–24 | doi = 10.1021/ic00241a001}}.</ref> | Other preparations of MnF<sub>4</sub> include the fluorination of MnF<sub>2</sub> with [[krypton difluoride]],<ref>{{citation | first1 = Karel | last1 = Lutar | first2 = Adolf | last2 = Jesih | first3 = Boris | last3 = Žemva | title = KrF<sub>2</sub>/MnF<sub>4</sub> adducts from KrF<sub>2</sub>/MnF<sub>2</sub> interaction in HF as a route to high purity MnF<sub>4</sub> | journal = Polyhedron | volume = 7 | issue = 13 | year = 1988 | pages = 1217–19 | doi = 10.1016/S0277-5387(00)81212-7}}.</ref> or with F<sub>2</sub> in liquid [[hydrogen fluoride]] solution under [[ultraviolet light]].<ref name="Mazej">{{citation | first = Z. | last = Mazej | title = Room temperature syntheses of MnF<sub>3</sub>, MnF<sub>4</sub> and hexafluoromanganete(IV) salts of alkali cations | journal = J. Fluorine Chem. | volume = 114 | issue = 1 | year = 2002 | pages = 75–80 | doi = 10.1016/S0022-1139(01)00566-8}}.</ref> Manganese tetrafluoride has also been prepared (but not isolated) in an acid–base reaction between [[antimony pentafluoride]] and K<sub>2</sub>MnF<sub>6</sub> as part of a chemical synthesis of elemental fluorine.<ref name="Christe">{{citation | first = Karl O. | last = Christe | year = 1986 | title = Chemical synthesis of elemental fluorine | journal = Inorg. Chem. | volume = 25 | issue = 21 | pages = 3721–24 | doi = 10.1021/ic00241a001}}.</ref> | ||
Revision as of 16:53, 12 September 2010
| Manganese tetrafluoride | |
|---|---|
| IUPAC name | manganese tetrafluoride |
| Other names | manganese(IV) fluoride |
| Identifiers | |
| InChI | InChI=1/4FH.Mn/h4*1H;/q;;;;+4/p-4 |
| Standard InChI | InChI=1S/4FH.Mn/h4*1H;/q;;;;+4/p-4 |
| Standard InChIKey | KWKYNMDHPVYLQQ-UHFFFAOYSA-J |
| CAS number | [] |
| Properties[1][2] | |
| Chemical formula | MnF4 |
| Molar mass | 130.93 g mol−1 |
| Appearance | blue solid |
| Melting point |
70 °C decomp. |
| Solubility in water | reacts violently |
| Related compounds | |
| Other cations | Manganese(II) fluoride Manganese(III) fluoride |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) | |
Manganese tetrafluoride, MnF4, is the highest fluoride of manganese. It is used as a powerful oxidizing agent and as a means of purifying elemental fluorine.[2][3]
Contents
Preparation
Manganese tetrafluoride was first unequivocally prepared in 1961[Note 1] by the reaction of manganese(II) fluoride (or other MnII compounds) with a stream of fluorine gas at 550 °C: the MnF4 sublimes into the gas stream and condenses onto a cold finger.[1][5] This is still the commonest method of preparation, although the sublimation can be avoided by operating at increased fluorine pressure (4.5–6 bar at 180–320 °C) and mechanically agitating the powder to avoid sintering of the grains.[2][6] The reaction can also be carried out starting from manganese powder in a fluidized bed.[7][8]
Other preparations of MnF4 include the fluorination of MnF2 with krypton difluoride,[9] or with F2 in liquid hydrogen fluoride solution under ultraviolet light.[10] Manganese tetrafluoride has also been prepared (but not isolated) in an acid–base reaction between antimony pentafluoride and K2MnF6 as part of a chemical synthesis of elemental fluorine.[11]
- K2MnF6 + 2 SbF5 → MnF4 + 2 KSbF6
Chemistry
Decomposition
Manganese tetrafluoride is in equilibrium with manganese(III) fluoride and elemental fluorine:
- MnF4 ⇌ MnF3 + ½ F2
Decomposition is favoured by increasing temperature, and disfavoured by the presence of fluorine gas, but the exact parameters of the equilibrium are unclear, with some sources saying that MnF4 will decompose slowly at room temperature,[12][13] others placing a practical lower temperature limit of 70 °C,[2] and another claiming that MnF4 is essentially stable up to 320 °C.[14] The equilibrium pressure of fluorine above MnF4 at room temperature has been estimated at about 10−4 Pa (10−9 bar), and the enthalpy change of reaction at +44(8) kJ mol−1.[15][Note 2]
Other reactions
Manganese tetrafluoride reacts violently with water and even with sodium dried petroleum ether. It immediately decomposes on contact with moist air.[1]
Reaction with alkali metal fluorides or concentrated hydrofluoric acid gives the yellow hexafluoromanganate(IV) anion [MnF6]2−.[14]
Applications
Fluoromanganate(IV) complexes
The yellow hexafluoromanganate(2−) of alkali metal and alkaline earth metal cations have been known since 1899, and can be prepared by the fluorination of MnF2 with the appropriate halide.[10][17][18][19] They are much more stable than manganese tetrafluoride.[11] Potassium hexafluoromanganate(IV), K2MnF6, can also be prepared by the controlled reduction of potassium permanganate in 50% aqueous hydrofluoric acid.[20][21]
- 2 KMnO4 + 2 KF + 10 HF + 3 H2O2 → 2 K2MnF6 + 8 H2O + 3 O2
The pentafluoromanganate(1−) salts of potassium, rubidium and caesium, MMnF5, can be prepared by fluorination of MMnF3 or by the reaction of [MnF4(py)(H2O)] with MF.[19][21] The lemon-yellow heptafluoromanganate(3−) salts of the same metals, M3MnF7, have also been prepared.[22]
Notes and references
Notes
- ↑ Reports of the preparation of MnF4 date back to the nineteenth century,[4] but are inconsistent with the now-known chemistry of the genuine compound.
- ↑ These two results are inconsistent with one another, as ΔrH
owould have to be about +80 kJ mol−1 for peq(F2) ≈ 10−9 bar at 298 K, given that the overwhelming contribution to ΔrSois So(F2) = 202.791(5) J K−1 mol−1.[16] The quoted value of ΔrHois consistent with most reported decomposition temperatures.
References
- ↑ 1.0 1.1 1.2 Hoppe, Rudolf; Dähne, Wolfgang; Klemm, Wilhelm Mangantetrafluorid, MnF4. Naturwissenschaften 1961, 48 (11), 429. DOI: 10.1007/BF00621676.
- ↑ 2.0 2.1 2.2 2.3 Torisu, Junichi; Oka, Masakazu; Kuznetsov, Andrey Sergeyevich, et al. (Astor Electronics/Showa Denko) Method of manufacturing manganese tetrafluoride. WO PCT Appl. 2006033480, published 30 March 2006.
- ↑ Seseke-Koyro, Ulrich; Garcia-Juan, Placido; Palsherm, Stefan, et al. (Solvay Fluor) Process for the purification of elemental fluorine. WO PCT Appl. 2009074562, published 18 June 2009.
- ↑ Melville, W. H. Contribution towards the History of the Fluorides of Manganese. Proc. Am. Acad. Arts Sci. 1876, 12, 228–34, <http://www.jstor.org/stable/25138452>.
- ↑ Hoppe, Rudolf; Dähne, Wolfgang; Klemm, Wilhelm Mangantetrafluorid mit einem Anhang über LiMnF5 und LiMnF4. Justus Liebigs Ann. Chem. 1962, 658 (1), 1–5. DOI: 10.1002/jlac.19626580102.
- ↑ Seseke-Koyro, Ulrich; Garcia-Juan, Placido; Palsherm, Stefan, et al. (Solvay Fluor) Method for preparing manganese tetrafluoride. WO PCT Appl. 2009074560, published 18 June 2009.
- ↑ Roesky, H.; Glemser, O. A New Preparation of Manganese Tetrafluoride. Angew. Chem., Int. Ed. Engl. 1963, 2 (10), 626. DOI: 10.1002/anie.196306262.
- ↑ Roesky, Herbert W.; Glemser, Oskar; Hellberg, Karl-Heinz Darstellung von Metallfluoriden in der Wirbelschicht. Chem. Ber. 1965, 98 (6), 2046–48. DOI: 10.1002/cber.19650980642.
- ↑ Lutar, Karel; Jesih, Adolf; Žemva, Boris KrF2/MnF4 adducts from KrF2/MnF2 interaction in HF as a route to high purity MnF4. Polyhedron 1988, 7 (13), 1217–19. DOI: 10.1016/S0277-5387(00)81212-7.
- ↑ 10.0 10.1 Mazej, Z. Room temperature syntheses of MnF3, MnF4 and hexafluoromanganete(IV) salts of alkali cations. J. Fluorine Chem. 2002, 114 (1), 75–80. DOI: 10.1016/S0022-1139(01)00566-8.
- ↑ 11.0 11.1 Christe, Karl O. Chemical synthesis of elemental fluorine. Inorg. Chem. 1986, 25 (21), 3721–24. DOI: 10.1021/ic00241a001.
- ↑ Cotton, F. Albert; Wilkinson, Geoffrey Advanced Inorganic Chemistry, 4th ed.; Wiley: New York, 1980; p 745. ISBN 0-471-02775-8.
- ↑ Housecroft, Catherine E.; Sharpe, Alan G. Inorganic Chemistry, 3rd ed.; Prentice Hall: New York, 2007; p 710. ISBN 0131755536.
- ↑ 14.0 14.1 Adelhelm, M.; Jacob, E. MnF4: preparation and properties. J. Fluorine Chem. 1991, 54 (1–3), 21. DOI: 10.1016/S0022-1139(00)83531-9.
- ↑ Ehlert, T. C.; Hsia, M. Mass spectrometric and thermochemical studies of the manganese fluorides. J. Fluorine Chem. 1972, 2 (1), 33–51. DOI: 10.1016/S0022-1139(00)83113-9.
- ↑ Cox, J. D.; Wagman, D. D.; Medvedev, V. A. CODATA Key Values for Thermodynamics; Hemisphere: New York, 1989. ISBN 0891167587, <http://www.codata.org/resources/databases/key1.html>.
- ↑ Weinland, R. F.; Lauenstein, O. Z. Anorg. Allg. Chem. 1899, 20, 40.
- ↑ Hoppe, Rudolf; Blinne, Klaus Hexafluoromanganate IV der Elemente Ba, Sr, Ca und Mg. Z. Anorg. Allg. Chem. 1957, 291 (5–6), 269–75. DOI: 10.1002/zaac.19572910507.
- ↑ 19.0 19.1 Hoppe, Rudolf; Liebe, Werner; Dähne, Wolfgang Über Fluoromanganate der Alkalimetalle. Z. Anorg. Allg. Chem. 1961, 307 (5–6), 276–89. DOI: 10.1002/zaac.19613070507.
- ↑ Bode, Hans; Jenssen, H.; Bandte, F. Über eine neue Darstellung des Kalium-hexafluoromanganats(IV). Angew. Chem. 1953, 65 (11), 304. DOI: 10.1002/ange.19530651108.
- ↑ 21.0 21.1 Chaudhuri, M. K.; Das, J. C.; Dasgupta, H. S. Reactions of KMnO4—A novel method of preparation of pentafluoromanganate(IV)[MnF5]−. J. Inorg. Nucl. Chem. 1981, 43 (1), 85–87. DOI: 10.1016/0022-1902(81)80440-X.
- ↑ Hofmann, B.; Hoppe, R. Zur Kenntnis des (NH4)3SiF7-Typs. Neue Metallfluoride A3MF7 mit M = Si, Ti, Cr, Mn, Ni und A = Rb, Cs. Z. Anorg. Allg. Chem. 1979, 458 (1), 151–62. DOI: 10.1002/zaac.19794580121.
Further reading
- Gubkina, N. I.; Sokolov, Sergey V.; Krylov, E. I. Fluorides of High Oxidising Power and Their Application to the Preparation of Organic Fluorine Compounds. Russ. Chem. Rev. 1966, 35 (12), 930–41. DOI: 10.1070/RC1966v035n12ABEH001550.
- Hoppe, R.; Müller, B.; Burgess, J.; Peacock, R. D.; Sherry, R. The enthalpy of formation of manganese tetrafluoride. J. Fluorine Chem. 1980, 16 (2), 189–91. DOI: 10.1016/S0022-1139(00)82393-3.
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