Molybdenum tetrachloride
Molybdenum tetrachloride is the inorganic compound with the empirical formula MoCl4. The material exists as two polymorphs, a polymeric ("α") and a hexameric ("β") structure. In each polymorph, the Mo center is octahedral with two terminal chloride ligands and four doubly bridging ligands.[1]
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| Names | |
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| IUPAC name
Molybdenum tetrachloride | |
| Other names
Molybdenum(IV) chloride | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.033.039  |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| Cl4Mo | |
| Molar mass | 237.752 g/mol |
| Appearance | black solid |
| Melting point | 552 °C (1,026 °F; 825 K) |
| Decomposes | |
| Hazards | |
| NFPA 704 (fire diamond) | |
| Flash point | Non flammable |
| Related compounds | |
Related compounds |
Molybdenum(II) chloride Molybdenum(III) chloride Molybdenum(V) chloride |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
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| Infobox references | |
Preparation
α-Molybdenum tetrachloride can be prepared from by dechlorination of molybdenum pentachloride using tetrachloroethene:[2]
- 2 MoCl5 + C2Cl4 → 2 MoCl4 + C2Cl6
Heating α-molybdenum tetrachloride in a sealed container in the presence of molybdenum pentachloride induces conversion to the β polymorph.[2]
Reactions
When heated in an open container, molybdenum tetrachloride evolves chlorine, giving molybdenum trichloride;[2]
- 2 MoCl4 → 2 MoCl3 + Cl2
The acetonitrile complex adduct can be prepared by reduction of the pentachloride with acetonitrile:[3][4]
- 2 MoCl5 + 5 CH3CN → 2 MoCl4(CH3CN)2 + ClCH2CN + HCl
The MeCN ligands can be exchanged with other ligands:
- MoCl4(CH3CN)2 + 2 THF → MoCl4(THF)2 + 2 CH3CN
References
- Ulrich Müller (1981). "Hexameric Molybdenum Tetrachloride". Angewandte Chemie International Edition in English. 20: 692. doi:10.1002/anie.198106921.
- McCann III, E. L.; Brown, T. M. (1970). "Molybdenum(IV) Chloride". Inorganic Syntheses. 12: 181. doi:10.1002/9780470132432.ch31.
- Broderick, Erin M.; Browne, Samuel C.; Johnson, Marc J. A. (2014). "Dimolybdenum and Ditungsten Hexa(Alkoxides)". Inorganic Syntheses. 36: 95–102. doi:10.1002/9781118744994.ch18.
- Dilworth, Jonathan R.; Richards, Raymond L. (1990). "The Synthesis of Molybdenum and Tungsten Dinitrogen Complexes". Inorganic Syntheses. 28: 33. doi:10.1002/9780470132593.ch7.