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Scandium is a chemical element with the symbol Sc and atomic number 21. It is a silvery-white metallic d-block element. Historically, it has been classified as a rare-earth element, [9] together with yttrium and the lanthanides. It was discovered in 1879 by spectral analysis of the minerals euxenite and gadolinite from Scandinavia. [10]
Scandium(III) oxide or scandia is a inorganic compound with formula Sc 2 O 3.It is one of several oxides of rare earth elements with a high melting point.It is used in the preparation of other scandium compounds as well as in high-temperature systems (for its resistance to heat and thermal shock), electronic ceramics, and glass composition (as a helper material).
In all four halides, the scandium is 6-coordinated. They can be prepared by reacting scandium oxide or scandium hydroxide with the corresponding acid: [3] Sc(OH) 3 + 3 HX → ScX 3 + 3 H 2 O. The halides are Lewis acids; for example, ScF 3 dissolves in a solution containing excess fluoride ion to form [ScF 6] 3−. The coordination number 6 is ...
Naturally occurring scandium (21 Sc) is composed of one stable isotope, 45 Sc. Twenty-seven radioisotopes have been characterized, with the most stable being 46 Sc with a half-life of 83.8 days, 47 Sc with a half-life of 3.35 days, and 48 Sc with a half-life of 43.7 hours and 44 Sc with a half-life of 3.97 hours.
Ce, La, and Nd are important in alloy making, and in the production of fuel cells and nickel-metal hydride batteries. Ce, Ga, and Nd are important in electronics and are used in the production of LCD and plasma screens, fiber optics, and lasers, [132] and in medical imaging. Additional uses for rare-earth elements are as tracers in medical ...
The reaction of scandium trichloride with two equivalents of sodium cyclopentadienide (NaCp) produces the chloride-bridged dimer: 2 ScCl 3 + 4 NaCp → [Cp 2 Sc(μ-Cl)] 2 + 4 NaCl. Cp 3 Sc is a polymer wherein one third of the Cp ligands serving as bridging ligands. [5] Bulkier cyclopentadienide ligands give monoscandium derivatives, e.g. (C 5 ...
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The most available element in group 3 is yttrium, with annual production of 8,900 tonnes in 2010. Yttrium is mostly produced as oxide, by a single country, China (99%). [75] Lutetium and scandium are also mostly obtained as oxides, and their annual production by 2001 was about 10 and 2 tonnes, respectively. [76]