Molybdenum tetrachloride

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Molybdenum tetrachloride
IUPAC name
Molybdenum tetrachloride
Other names
Molybdenum(IV) chloride
3D model (JSmol)
ECHA InfoCard 100.033.039 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
  • InChI=1S/4ClH.Mo/h4*1H;/q;;;;+4/p-4 X mark.svgN
  • InChI=1/4ClH.Mo/h4*1H;/q;;;;+4/p-4/rCl4Mo/c1-5(2,3)4
  • Cl[Mo](Cl)(Cl)Cl
Molar mass 237.752 g/mol
Appearanceblack solid
Melting point 552 °C (1,026 °F; 825 K)
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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Molybdenum tetrachloride is the inorganic compound with the empirical formula MoCl4. The material exists as two polymorphs, both being dark-colored paramagnetic solids. These compounds are mainly of interest as precursors to other molybdenum complexes.



The α polymorph is a polymer. The β polymorph is a hexamer. In both polymorph, the Mo center is octahedral with two terminal chloride ligands and four doubly bridging ligands. [1] In addition to these two binary phases, a number of adducts are know with the formula MoCl4L2 where L is a Lewis base.


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]


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

The pentachloride can be reduced to the ether complex MoCl4(Et2O)2 using tin powder. It is a beige, paramagnetic solid. [5]

Related Research Articles

Titanium tetrachloride Inorganic chemical compound

Titanium tetrachloride is the inorganic compound with the formula TiCl4. It is an important intermediate in the production of titanium metal and the pigment titanium dioxide. TiCl4 is a volatile liquid. Upon contact with humid air, it forms thick clouds of titanium dioxide and hydrochloric acid, a reaction that was formerly exploited for use in smoke machines. It is sometimes referred to as "tickle" or "tickle 4" due to the phonetic resemblance of its molecular formula to the word.

Palladium(II) chloride Chemical compound

Palladium(II) chloride, also known as palladium dichloride and palladous chloride, are the chemical compounds with the formula PdCl2. PdCl2 is a common starting material in palladium chemistry – palladium-based catalysts are of particular value in organic synthesis. It is prepared by the reaction of chlorine with palladium metal at high temperatures.

Tantalum(V) chloride Chemical compound

Tantalum(V) chloride, also known as tantalum pentachloride, is an inorganic compound with the formula TaCl5. It takes the form of a white powder and is commonly used as a starting material in tantalum chemistry. It readily hydrolyzes to form tantalum(V) oxychloride (TaOCl3) and eventually tantalum pentoxide (Ta2O5); this requires that it be synthesised and manipulated under anhydrous conditions, using air-free techniques.

Chromium hexacarbonyl Chemical compound

Chromium carbonyl, also known as chromium hexacarbonyl, is the chemical compound with the formula Cr(CO)6. At room temperature the solid is stable to air, although it does have a high vapor pressure and sublimes readily. Cr(CO)6 is zerovalent, meaning that Cr has an oxidation state of zero, and it is a homoleptic complex, which means that all the ligands are identical. The complex is octahedral with Cr–C and C–O distances of 1.91 and 1.14 Å, respectively.

Titanium(III) chloride is the inorganic compound with the formula TiCl3. At least four distinct species have this formula; additionally hydrated derivatives are known. TiCl3 is one of the most common halides of titanium and is an important catalyst for the manufacture of polyolefins.

Vanadium tetrachloride is the inorganic compound with the formula VCl4. This bright red liquid serves as a useful reagent for the preparation of other vanadium compounds.

Vanadium(III) chloride Chemical compound

Vanadium trichloride is the inorganic compound with the formula VCl3. This purple salt is a common precursor to other vanadium(III) complexes.

Molybdenum(V) chloride Chemical compound

Molybdenum(V) chloride is the inorganic compound with the formula [MoCl5]2. This dark volatile solid is used in research to prepare other molybdenum compounds. It is moisture-sensitive and soluble in chlorinated solvents. Usually called molybdenum pentachloride, it is in fact a dimer with the formula Mo2Cl10.

Molybdenum(II) chloride Chemical compound

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.

Cyclopentadienylmolybdenum tricarbonyl dimer Chemical compound

Cyclopentadienylmolybdenum tricarbonyl dimer is the chemical compound with the formula Cp2Mo2(CO)6, where Cp is C5H5. A dark red solid, it has been the subject of much research although it has no practical uses.

Niobium(IV) chloride Chemical compound

Niobium(IV) chloride, also known as niobium tetrachloride, is the chemical compound of formula NbCl4. This compound exists as dark violet crystals, is highly sensitive to air and moisture, and disproportiates into niobium(III) chloride and niobium(V) chloride when heated.

Metal halides

Metal halides are compounds between metals and halogens. Some, such as sodium chloride are ionic, while others are covalently bonded. A few metal halides are discrete molecules, such as uranium hexafluoride, but most adopt polymeric structures, such as palladium chloride.

Molybdenum(III) chloride Chemical compound

Molybdenum(III) chloride is the inorganic compound with the formula MoCl3. It forms purple crystals.

Bis(dinitrogen)bis(1,2-bis(diphenylphosphino)ethane)molybdenum(0) Chemical compound

trans-Bis(dinitrogen)bis[1,2-bis(diphenylphosphino)ethane]molybdenum(0) is a coordination complex with the formula Mo(N2)2(dppe)2. It is a relatively air stable yellow-orange solid. It is notable as being the first discovered dinitrogen containing complex of molybdenum.

Tungsten(IV) chloride is an inorganic compound with the formula WCl4. It is a diamagnetic black solid. The compound is of interest in research as one of a handful of binary tungsten chlorides.

Bis(benzonitrile)palladium dichloride Chemical compound

Bis(benzonitrile)palladium dichloride is the coordination complex with the formula PdCl2(NCC6H5)2. It is the adduct of two benzonitrile (PhCN) ligands with palladium(II) chloride. It is a yellow-brown solid that is soluble in organic solvents. The compound is a reagent and a precatalyst for reactions that require soluble Pd(II). A closely related compound is bis(acetonitrile)palladium dichloride.

Transition metal nitrile complexes Class of coordination compounds containing nitrile ligands (coordinating via N)

Transition metal nitrile complexes are coordination compounds containing nitrile ligands. Because nitriles are weakly basic, the nitrile ligands in these complexes are often labile.

Molybdenum oxytetrachloride Chemical compound

Molybdenum oxytetrachloride is the inorganic compound with the formula MoOCl4. This thermally unstable, dark green solid is used to prepare other complexes of molybdenum. It adopts a square pyramidal structure of C4v symmetry. As for other Mo(VI) compounds, it is diamagnetic. It decomposes thermally to MoOCl3.

Transition metal chloride complex Coordination complex

In chemistry, a transition metal chloride complex is a coordination complex that consists of a transition metal coordinated to one or more chloride ligand. The class of complexes is extensive.

Transition metal ether complex

In chemistry, a transition metal ether complex is a coordination complex consisting of a transition metal bonded to one or more ether ligand. The inventory of complexes is extensive. Common ether ligands are diethyl ether and tetrahydrofuran. Common chelating ether ligands include the glymes, dimethoxyethane (dme) and diglyme, and the crown ethers. Being lipophilic, metal-ether complexes often exhibit solubility in organic solvents, a property of interest in synthetic chemistry.


  1. Ulrich Müller (1981). "Hexameric Molybdenum Tetrachloride". Angewandte Chemie International Edition in English. 20 (8): 692. doi:10.1002/anie.198106921.
  2. 1 2 3 McCann III, E. L.; Brown, T. M. (1970). "Molybdenum(IV) Chloride". Inorganic Syntheses. Inorganic Syntheses. Vol. 12. p. 181. doi:10.1002/9780470132432.ch31. ISBN   9780470132432.
  3. Broderick, Erin M.; Browne, Samuel C.; Johnson, Marc J. A. (2014). "Dimolybdenum and Ditungsten Hexa(Alkoxides)". Inorganic Syntheses: Volume 36. Inorganic Syntheses. Vol. 36. pp. 95–102. doi:10.1002/9781118744994.ch18. ISBN   9781118744994.
  4. Dilworth, Jonathan R.; Richards, Raymond L. (1990). "The Synthesis of Molybdenum and Tungsten Dinitrogen Complexes". Inorganic Syntheses. Inorganic Syntheses. Vol. 28. p. 33. doi:10.1002/9780470132593.ch7. ISBN   9780470132593.
  5. Maria, Sébastien; Poli, Rinaldo (2014). "Ether Complexes of Molybdenum(III) and Molybdenum(IV) chlorides". Inorganic Syntheses: Volume 36. Inorganic Syntheses. Vol. 36. pp. 15–18. doi:10.1002/9781118744994.ch03. ISBN   9781118744994.