cerium Chem.
(ˈsɪərɪəm)
[Named by Hisinger and Berzelius, along with its source cerite, after the planet Ceres, whose discovery (in 1801) was then one of the most striking facts in physical science. The ending is as in potassium and other names of metals. Klaproth, in 1807, changed the names to cererium and cererite ‘lest they should appear to be derived from cēra, κηρός wax’, but the change was not accepted (Dana).]
One of the chemical elements: a rare metal, discovered in the mineral called cerite; it has the colour and lustre of iron, and takes a high polish, which it retains in dry air, but in moist air it becomes covered with coloured films like heated steel; it is malleable and ductile, of specific gravity 6·63 to 6·73. Atomic weight 138; symbol Ce.
| 1804 W. Nicholson Jrnl. Nat. Phil. IX. 290 (title) Account of Cerium, a New Metal found in a Mineral Substance from Bastnas in Sweden. 1808 Henry Epit. Chem. (ed. 5) 266 From the planet Ceres, discovered about the same period, it has been called Cerium; and the mineral that contains it is termed Cerite. 1812 Sir H. Davy Chem. Philos. 433 Cerium had not been obtained in the metallic form till I succeeded in reducing some oxide sent me by M. Berzelius, by means of potassium..[forming] a deep gray metallic powder, which became brown by oxidation. 1844–68 Dana Min. 414 In 1839 Mosander proved that the oxyd of cerium contained the new metal lanthanum, and in 1842 another new metal didymium. 1865 A. H. Church in Chem. News XII. 121 A new British mineral containing cerium. 1875 Ure Dict. Arts I. 757 Cerium has also been detected by Prof. Church in a Cornish mineral. |
b. attrib.: in cerium compounds, cerium group (of metals), cerium salts, etc. = ceric1.
| 1879 Watts Dict. Chem. 2nd Supp. 273 Preparation of pure cerium salts. Ibid. 3rd Supp. 420 A piece of cerium wire burns with even greater brilliancy than magnesium. 1886 Roscoe Elem. Chem. 166 Class VI, Cerium Group. |