 Partially oxidized MoCl5 | |
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| Names | |
|---|---|
| IUPAC names Molybdenum(V) chloride Molybdenum pentachloride | |
| Identifiers | |
3D model (JSmol) | |
| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.030.510 |
| EC Number |
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| RTECS number |
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| UNII | |
| UN number | 2508 |
| |
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| Properties | |
| Mo2Cl10 | |
| Molar mass | 273.21 g/mol (MoCl5) |
| Appearance | dark-green solid hygroscopic paramagnetic |
| Density | 2.928 g/cm3 |
| Melting point | 194 °C (381 °F; 467 K) |
| Boiling point | 268 °C (514 °F; 541 K) |
| hydrolyzes | |
| Solubility | soluble in dryether, dryalcohol,organic solvents |
| Structure | |
| monoclinic | |
| edge-shared bioctahedron | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards | oxidizer, hydrolyzes to release HCl |
| GHS labelling:[1] | |
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| Danger | |
| H314 | |
| P260,P264,P280,P301+P330+P331,P302+P361+P354,P304+P340,P305+P354+P338,P316,P321,P363,P405,P501 | |
| Flash point | Non-flammable |
| Related compounds | |
Otheranions | |
Othercations | |
Related molybdenum chlorides | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Molybdenum(V) chloride is theinorganic compound with theempirical formulaMoCl5. This dark volatile solid is used in research to prepare other molybdenum compounds. It is moisture-sensitive and soluble in chlorinated solvents.
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Usually called molybdenum pentachloride, it is in fact partly adimer with themolecular formulaMo2Cl10.[1] In the dimer, each molybdenum has local octahedral symmetry and two chloridesbridge between the molybdenum centers.[2] A similar structure is also found for the pentachlorides of W, Nb and Ta.[3] In the gas phase and partly in solution, thedimers partially dissociate to give a monomericMoCl5.[4] The monomer is paramagnetic, with one unpaired electron per Mo center, reflecting the fact that the formal oxidation state is +5, leaving one valence electron on the metal center.
MoCl5 is prepared by chlorination of Mo metal but also chlorination ofMoO3. The unstable hexachlorideMoCl6 is not produced in this way.[5]
MoCl5 is reduced by acetonitrile to afford an orangeacetonitrile complex,MoCl4(CH3CN)2. This complex in turn reacts withTHF to giveMoCl4(THF)2, a precursor to other molybdenum-containing complexes.[6]
Molybdenum(IV) bromide is prepared by treatment ofMoCl5 withhydrogen bromide:
The reaction proceeds via the unstable molybdenum(V) bromide, which releases bromine at room temperature.[7]
MoCl5 is a goodLewis acid toward non-oxidizable ligands. It forms an adduct with chloride to form[MoCl6]−. Inorganic synthesis, the compound finds occasional use inchlorinations,deoxygenation, and oxidative coupling reactions.[8]
MoCl5 is reduced byacetonitrile:[9]
Although it polymerizestetrahydrofuran,MoCl5 is stable indiethyl ether. Reduction of such solutions with tin givesMoCl4((CH3CH2)2O)2 andMoCl3((CH3CH2)2O)3, depending on conditions.[10]
MoCl5 is an aggressive oxidant and readily hydrolyzes to release HCl.
