is the inorganic compound
with the formula TiCl<sub>3</sub>. At least four distinct species have this formula; additionally hydrated
derivatives are known. TiCl<sub>3</sub> is one of the most common halides of titanium and is an important catalyst for the manufacture of polyolefins
In TiCl<sub>3</sub>, each Ti atom has one d
electron, rendering its derivatives paramagnetic
, i.e. the substance is attracted into a magnetic field. The paramagnetism contrasts with the diamagnetism
(the property of being repelled from a magnetic field) of the trihalides of hafnium and zirconium: in these heavier metals engage in metal-metal bonding.
Solutions of titanium(III) chloride are violet, which arises from excitations
of its d-electron
. The colour is not very intense since the transition is forbidden
by the Laporte selection rule.
Four solid forms or polymorphs
of TiCl<sub>3</sub> are known. All feature titanium in an octahedral coordination sphere. These forms can be distinguished by crystallography
as well as by their magnetic properties, which probes exchange interactions
. β-TiCl<sub>3</sub> crystallizes as brown needles. Its structure consists of chains of TiCl<sub>6</sub> octahedra that share opposite faces such that the closest Ti—Ti contact is 2.91 Å. This short distance indicates strong metal-metal interactions (See Figure in upper right). The... Read More