Prepn from Ce sulfate and Ca(NO3)2: Blumenfeld, US 2166702 (1939 to Soc. de Produits Chimiques des Terres Rares); in separation of cerium from other rare earths: Pierce, Butler, Inorg. Synth. 2, 51 (1946); Scargill et al., J. Inorg. Nucl. Chem. 4, 304 (1957). For physical and chemical properties see USAEC IDO-14504, 126 pp (1961). Toxicity study: Bruce et al., Toxicol. Appl. Pharmacol. 5, 750 (1963).