This chromium(II) compound undergoes substitution easily, and it can exchange electrons with CrCl 3 via a chloride bridge, allowing all of the CrCl 3 to react quickly. One way of opening CrCl 3 up to substitution in solution is to reduce even a trace amount to CrCl 2, for example using zinc in hydrochloric acid. The low reactivity of the d 3 Cr 3+ ion can be explained using crystal field theory. However it is also a chloro complex which is quite inert to substitution, so in fact it is ordinarily quite unreactive. It reacts as a Lewis acid, forming stable chloro complexes such as 3-.Ĭhromium(III) chloride is a Lewis acid, classified as "hard" according to the Hard-Soft Acid-Base theory. When it does react it undergoes ligand substitution reactions to form other complexes of chromium(III). This inertness means that CrCl 3 is generally sluggish to react without the presence of a reducing agent. The common commercial form of the hydrate is the dark green complex shown in the picture, Cl.2H 2O, but two other forms are known, viz., pale green Cl 2.H 2O and violet Cl 3. However, in the presence of a trace of a reducing agent capable of reducing Cr 3+ to Cr 2+, the CrCl 3 dissolves rapidly to form soluble complexes containing hydrated Cr 3+ ions.
Molybdenum(III) chloride Tungsten(III) chlorideĬhromium(II) chloride Chromium(IV) chlorideĮxcept where noted otherwise, data are given for materials in their standard state (at 25 ☌, 100 kPa) Infobox disclaimer and referencesĬhromium(III) chloride (also called chromic chloride) is a violet coloured solid with the formula CrCl 3.Īlthough it is ionic, the solid state structure is kinetically inert so that anhydrous CrCl 3 is surprisingly reluctant to dissolve in water. Chromium(III) chloride Chromium trichlorideĬhromium(III) fluoride Chromium(III) bromide Chromium(III) iodide