Molybdenum(II) chloride
 |
|
| Names | |
|---|---|
|
IUPAC name
dodecachlorohexamolybdenum(II)
|
|
| Other names
molybdenum(II) chloride
|
|
| Identifiers | |
| 11062-51-4 | |
| 3D model (Jmol) | Interactive image |
| ChemSpider | 75349 |
| ECHA InfoCard | 100.033.417 |
| PubChem | 83514 |
|
|
|
|
| Properties | |
| Cl12Mo6 | |
| Appearance | orange solid |
| low | |
|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|
|
| Infobox references | |
Molybdenum dichloride describes chemical compounds with the empirical formula MoCl2. At least two forms are known, and both have attracted much attention from academic researchers because of the unexpected structures seen for these compounds and the fact that they give rise to hundreds of derivatives. The form discussed here is Mo6Cl12. The other molybdenum(II) chloride is potassium octachlorodimolybdate.
Rather than adopting a close-packed structure typical of metal dihalides, e.g., cadmium chloride, molybdenum(II) chloride forms a structure based on clusters. Molybdenum(II), which is a rather large ion, prefers to form compounds with metal-metal bonds, i.e. metal clusters. In fact all "lower halides" (i.e. where halide/M ratio is <4) in the "early transition metal series (Ti, V, Cr, Mn triads) do. The species Mo6Cl12 is polymeric, consisting of cubic Mo6Cl84+ clusters interconnected by chloride ligands that bridge from cluster to cluster. This material converts readily to salts of the dianion [Mo6Cl14]2−. In this anion, each Mo bears one terminal chloride but is otherwise part of an Mo6 octahedron embedded inside a cube defined by eight chloride centers. Thus, the coordination environment of each Mo is four triply bridging chloride ligands, four Mo neighbors, and one terminal Cl. The cluster has 24e−, four being provided by each Mo2+.
Mo6Cl12 is prepared by the reaction of molybdenum(V) chloride with molybdenum metal:
This reaction proceeds via the intermediacy of MoCl3 and MoCl4, which also are reduced by the presence of excess Mo metal. The reaction is conducted in a tube furnace at 600–650 °C.
Once isolated, Mo6Cl12 undergoes many reactions with retention of the Mo612+ core. Heating in concentrated HCl gives (H3O)2[Mo6Cl14]. The terminal chloride ligands, labeled "ausser" are readily exchanged:
...
Wikipedia