Chem. Also 9 lant(h)anium. [f. Gr. λανθάν-ειν to escape notice (see quot. 1841).] A rare element belonging to the group of earth metals, found in certain rare minerals, e.g., cerite; it was discovered by Mosander 1839–41. Symbol Ln. Also attrib.
1841. Brande, Man. Chem. (ed. 5), 877. Another metallic oxide, which, as it has hitherto lain concealed in oxide of cerium, he [Mosander] designates Lantanum (λανθανειν, to lurk).
1842. Parnell, Chem. Anal. (1845), 338. Oxide of lantanium.
1849. D. Campbell, Inorg. Chem., 167. Lanthanum.
1863. Fownes, Chem. (ed. 9), 320. Metallic lanthanium is prepared like cerium. Ibid. A tolerably pure lanthanium salt may be obtained by [etc.]. Ibid. (1873), (ed. 11), 381. Lanthanum Sulphate forms small prismatic crystals.
