It is a white hygroscopic salt; it rapidly absorbs water on exposure to moist air to form a hydrate, which appears to be of variable composition,[1] though the heptahydrate CeCl3·7H2O is known.

[3] A useful form of anhydrous CeCl3 can be prepared if care is taken to heat the heptahydrate gradually to 140 °C (284 °F) over many hours under vacuum.

[14] Luche reduction[15] of alpha, beta-unsaturated carbonyl compounds has become a popular method in organic synthesis, where CeCl3·7H2O is used in conjunction with sodium borohydride.

Another important use in organic synthesis is for alkylation of ketones, which would otherwise form enolates if simple organolithium reagents were to be used.

For example, compound 3 would be expected to simply form an enolate without CeCl3 being present, but in the presence of CeCl3 smooth alkylation occurs: [4]