Indium(III) chloride

Indium(III) chloride is the chemical compound with the formula InCl3. This colorless salt finds some use in organic synthesis as a Lewis acid. It is also the most available soluble derivatives of indium.

Synthesis and structure
Being a relatively electropositive metal, indium reacts readily with chlorine to give the trichloride. A synthesis has been reported using an electrochemical cell in a mixed methanol-benzene solution.

Like AlCl3 and TlCl3, InCl3 crystallizes as a layered structure consisting of close-packed chloride arrangement containing layers of In(III) centers. The motif is akin to that seen for YCl3. In contrast, GaCl3 and InI3 crystallize as dimers containing Ga2Cl6 and In2I6 subunits, respectively.

Catalyst in chemistry
Indium chloride is a lewis acid catalyst in organic reactions such as Friedel-Crafts acylations and Diels-Alder reactions. As an example of the latter The reaction proceeds at room temperature, with 1 mole% catalyst loading in an acetonitrile-water solvent mixture. The first step is a Knoevenagel condensation between the barbituric acid and the aldehyde, the second step is a reverse electron-demand Diels-Alder reaction.


 * [[Image:IndiumChlorideApplication.png|400px|Indium chloride application, reaction product is mixture of cis-trans isomers]]

which is a multicomponent reaction of N.N'-dimethyl-barbituric acid, benzaldehyde and ethyl vinyl ether. With catalyst the reported chemical yield is 90% and the percentage trans isomer is 70%. Without the catalyst added the yield drops to 65% with 50% trans product.