Manganese(IV) chloride
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| Cl4Mn | |
| Molar mass | 196.74 g·mol−1 |
| Appearance | brown solution |
| Melting point | −26 °C (−15 °F; 247 K) |
| Soluble, reacts | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Manganese tetrachloride is a binary inorganic compound of manganese and chlorine with the chemical formula MnCl4.[1]
Synthesis
Pure manganese(IV) chloride has never been isolated.[2] According to Holleman and Wiberg (2016), it is likely to be an intermediate in the reaction between manganese dioxide and hydrogen chloride gas:[3]: 1907
- MnO2 + 4 HCl → MnCl4 + 2 H2O
- MnCl4 → MnCl2 + Cl2
Earlier works claim the compound is formed by treating manganese dioxide with cold, concentrated hydrochloric acid, resulting in a dark-brown solution.[4][5]
Other reactions with higher oxides are also possible:[6]
- Mn2O3 + 6 HCl → MnCl4 + MnCl2 + 3H2O
- Mn3O4 + 8 HCl → MnCl4 + 2 MnCl2 + 4H2O
MnCl4 is thermally unstable and liberates chlorine gas during these reactions and in solution at STP.[7]
Physical properties
The metal chloride is a highly unstable, dark-brown compound that easily decomposes, though a stable form can exist in solution at low temperatures, usually in the form of MnCl2−6 or MnCl−5 coordination-complex anions with excess HCl/H3O+ which then decompose favorably on formation of neutral MnCl4.[8] MnCl4 is often distinguished from the more common and stable manganese(II) chloride (MnCl2).[9]
Reactions
A reagent for the α-chlorination of enolizable ketones, derived from the reaction of manganese(IV) oxide with chlorotrimethylsilane ((CH3)3SiCl) or acetyl chloride (CH3COCl), is claimed to contain manganese(IV) chloride.[10][11]
References
- ↑ Biltz, Heinrich (7 January 2021) [1909]. Introduction to Experimental Inorganic Chemistry. Walter de Gruyter GmbH & Co KG. p. 124. ISBN 978-3-11-235658-6.
- ↑ Collomb, Marie-Noëlle; Deronzier, Alain (2005). "Manganese: Inorganic & Coordination Chemistry" (PDF). In King, Robert Bruce (ed.). Encyclopedia of Inorganic Chemistry (2nd ed.). Chichester: J. Wiley & Sons. doi:10.1002/0470862106.ia126. ISBN 9780470860786.
- ↑ Holleman, Arnold F. [at Wikidata]; Wiberg, Egon; Wiberg, Nils [in German] (2016). Anorganische Chemie, Band 2, Nebengruppenelemente, Lanthanoide, Actinoide, Transactinoide [Inorganic Chemistry, Vol. 2: Transition Elements, Lanthanides, Actinides, Transactinides] (in German) (103 ed.). Berlin: De Gruyter. ISBN 978-3-11-049590-4. OCLC 960038226.
- ↑ Jago, William (1889). Inorganic Chemistry, Theoretical & Practical, with an Introduction to the Principles of Chemical Analysis Inorganic and Organic: An Elementary Text-book. Longmans, Green, and Company. p. 83.
- ↑ Sidgwick, Nevil Vincent (1951). The Chemical Elements and Their Compounds. Vol. 2. Oxford University Press. pp. 1273–1274.
- ↑ The London, Edinburgh and Dublin Philosophical Magazine and Journal of Science. Taylor & Francis. 1891. p. 484.
- ↑ (STP is 25C/77F 101.3kPa)
- ↑ Blount, Bertram; Bloxam, Arthur George (1900). Chemistry for Engineers and Manufacturers: Chemistry of manufacturing processes. C. Griffin. p. 35.
- ↑ Vernon, H. M. (1 June 1891). "LIX. On manganese tetrachloride". The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science. 31 (193): 469–484. doi:10.1080/14786449108620146. ISSN 1941-5982.
- ↑ Jean Suffert. "α-Heterosubstituted Ketones | 26.6.2.1.1.5 Variation 5: Direct Chlorination with Manganese(IV) Chloride". Thieme Gruppe. Science of Synthesis.
- ↑ Bellesia F, Ghelfi F, Pagnoni UM, Pinetti A (1990). "The Chlorination of Ketones with Manganese(IV) Chloride". Journal of Chemical Research (6): 188–189.