Chromium(III) chloride ( chromic chloride)supplier Distributor Manufacturer in Kolkata West Bengal india

Chromium(III) chloride (also called chromic chloride) describes any of several compounds of with the formula CrCl3 · xH2O, where x can be 0, 5, and 6. The anhydrous compound with the formula CrCl3 is a violet solid. The most common form of the trichloride is the dark green "hexahydrate", CrCl3 · 6H2O. Chromium chloride finds uses as catalysts and as precursors to dyes for wool.

Chromium(III) chloride hydrates

Chromium(III) chlorides display the somewhat unusual property of existing in a number of distinct chemical forms (isomers), which differ in terms of the number of chloride anions that are coordinated to Cr(III) and the water of crystallization. The different forms exist both as solids, and in aqueous solutions. Several members are known of the series of [CrCl3−n(H2O)n]z+. The main hexahydrate can be more precisely described as [CrCl2(H2O)4]Cl · 2H2O. It consists of the cation trans-[CrCl2(H2O)4]+ and additional molecules of water and a chloride anion in the lattice. Two other hydrates are known, pale green [CrCl(H2O)5]Cl2 · H2O and violet [Cr(H2O)6]Cl3. Similar behaviour occurs with other chromium(III) compounds.

Use in organic synthesis

One niche use of CrCl3 in organic synthesis is for the in situ preparation of chromium(II) chloride, a reagent for the reduction of alkyl halides and for the synthesis of (E)-alkenyl halides. The reaction is usually performed using two moles of CrCl3 per mole of lithium aluminium hydride, although if aqueous acidic conditions are appropriate zinc and hydrochloric acid may be sufficient.

Chromium(III) chloride has also been used as a Lewis acid in organic reactions, for example to catalyse the nitroso Diels-Alder reaction.

Dyestuffs

A number of chromium-containing dyes are used commercially for wool. Typical dyes are triarylmethanes consisting of ortho-hydroxylbenzoic acid derivatives.