Similar to the chlorides of other platinum group metals, rhodium chloride readily forms double salts with alkali chlorides. The chloride is obtainable also as a water-sol hydrate with variable amounts of water. Prepn of trihydrate: Anderson, Basolo, Inorg. Synth. 7, 214 (1963). Toxicity data: Landolt et al., Toxicol. Appl. Pharmacol. 21, 589 (1972).