Molybdenum(III) chloride is the
inorganic compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...
with the formula MoCl
3. It forms purple crystals.
Synthesis and structure
Molybdenum(III) chloride is synthesized by the
reduction of
molybdenum(V) chloride with
hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...
. A higher yield is produced by the reduction of pure molybdenum(V) chloride with anhydrous
tin(II) chloride
Tin(II) chloride, also known as stannous chloride, is a white crystalline solid with the formula . It forms a stable dihydrate, but aqueous solutions tend to undergo hydrolysis, particularly if hot. SnCl2 is widely used as a reducing agent (in aci ...
as the
reducing agent
In chemistry, a reducing agent (also known as a reductant, reducer, or electron donor) is a chemical species that "donates" an electron to an (called the , , , or ).
Examples of substances that are commonly reducing agents include the Earth meta ...
.
Molybdenum trichloride exists as two
polymorphs: alpha (α) and beta (β). The alpha structure is similar to that of
aluminum chloride (AlCl
3). In this structure, molybdenum has octahedral coordination geometry and exhibits cubic
close-packing
In geometry, close-packing of equal spheres is a dense arrangement of congruent spheres in an infinite, regular arrangement (or lattice). Carl Friedrich Gauss proved that the highest average density – that is, the greatest fraction of space occu ...
in its crystalline structure. The beta structure, however, exhibits hexagonal close packing.
Ether complexes
Molybdenum trichloride gives a
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. Com ...
es MoCl
3(thf)
3 and MoCl
3(Et
2O)
3. They are beige, paramagnetic solids. Both feature octahedral Mo centers. The
diethyl ether
Diethyl ether, or simply ether, is an organic compound in the ether class with the formula , sometimes abbreviated as (see Pseudoelement symbols). It is a colourless, highly volatile, sweet-smelling ("ethereal odour"), extremely flammable liq ...
complex is synthesized by reducing a Et
2O solution of MoCl
5 with tin powder. Older procedures involve stepwise reduction involving isolation of the Mo(IV)-thf complex.
Hexa(tert-butoxy)dimolybdenum(III) is prepared by the
salt metathesis reaction from MoCl
3(thf)
3:
:2 MoCl
3(thf)
3 + 6 LiOBu-t → Mo
2(OBu-t)
6 + 6 LiCl + 6 thf
References
Chlorides
Molybdenum halides
Molybdenum(III) compounds
{{Inorganic-compound-stub