Scandium(III) chloride is an ionic compound also known as scandium chloride and scandium trichloride. It is composed of one scandium and three chlorine atoms. Each chlorine atom takes one of scandium’s three valence electrons, resulting in 3Cl- and Sc3+. The ensuing formula is ScCl3.
Scandium(III) chloride is a white crystalline solid with the formula ScCl3. Typical for an ionic solid, it is high-melting, liquefying at 960 °C. Both exhibit hexagonal close-packed (hcp) crystal structures, but it is their bond energy that accounts for the melting points’ difference.
Scandium(III) chloride is primarily of interest in the research laboratory and numerous suppliers (see below) offer both the anhydrous form and hexahydrate (ScCl3•6H2O).
Like other compounds of Sc, the chlorides are dominated by the III oxidation state. Interesting reduced forms of Sc can however be prepared by reducing the trichloride with Sc metal (see below).
Scandium(III) chloride’s was used in the first preparation of metallic scandium in 1937. Fischer and collaborators synthesized the metal through an electrolysis of a eutectic melt of scandium(III) chloride and other salts at 700-800 °C..
Reaction of ScCl3 with tetrahydrofuran yields ScCl3(THF)3 as white crystals. This THF-soluble complex is a key synthetic intermediate.
ScCl3 has been converted to its dodecyl sulfate salt, which is used as a "Lewis acid-surfactant combined catalyst" (LASC) in aldol-like reactions.
ScCl3 has proven to be reactive toward Sc metal to give rise to a broad family of scandium chlorides where the Sc has an oxidation state <3.
Sc(s) + ScCl3 (950 °C) → Sc5Cl8
Sc(s) + ScCl3 (890 °C) → Sc7Cl12 → Sc(Sc6Cl12)
Scandium(III) chloride is found in halide lamps, optical fibers, electronic ceramics, and lasers.
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^ Frederikse, H.P.R.; Lide, David R. (1998). CRC Handbook of Chemistry and Physics (78th Edition).
^ Subbarao, E.C.; Wallace, W.E. (1980) Science and Technology of Rare Earth Metals. (Academic Press) pp. 16
^ Metal Suppliers Online. (2000). Scandium Chloride.
^ Metall Rare Earth Limited. (2006). Scandium Chloride
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