Scandium(III) chloride is the

inorganic compound An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds⁠that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''. Inorgan ...

with the

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...

ScCl₃. It is a white, high-melting

ionic compound In chemistry, a salt or ionic compound is a chemical compound consisting of an assembly of positively charged ions (Cation, cations) and negatively charged ions (Anion, anions), which results in a compound with no net electric charge (electrica ...

, which is

deliquescent Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption (chemistry), absorption or adsorption from the surrounding Natural environment, environment, which is usually at normal or room temperature. If water mol ...

and highly water-soluble. This salt is mainly of interest in the research laboratory. Both the

anhydrous A substance is anhydrous if it contains no water. Many processes in chemistry can be impeded by the presence of water; therefore, it is important that water-free reagents and techniques are used. In practice, however, it is very difficult to achie ...

form and hexahydrate (ScCl₃•6H₂O) are commercially available.

Structure

ScCl₃ crystallises in the layered BiI₃ motif, which features octahedral scandium centres. Monomeric ScCl₃ is the predominant species in the vapour phase at 900 K, the dimer Sc₂Cl₆ accounts for approximately 8%.Haaland A., Martinsen K-G, Shorokhov D.J, Girichev G.V., Sokolov V.I, J. Chem. Soc., Dalton Trans., 1998, 2787 - 2792, The electron diffraction spectrum indicates that the

monomer A monomer ( ; ''mono-'', "one" + '' -mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or two- or three-dimensional network in a process called polymerization. Classification Chemis ...

is planar and the dimer has two bridging Cl atoms each Sc being 4 coordinate.

Reactions

ScCl₃ is a Lewis acid that absorbs water to give aquo complexes. According to X-ray crystallogrphy, one such hydrate is the salt ''trans''- cCl₂(H₂O)₄l·2H₂O. With the less basic

ligand In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's el ...

tetrahydrofuran Tetrahydrofuran (THF), or oxolane, is an organic compound with the formula (CH2)4O. The compound is classified as heterocyclic compound, specifically a cyclic ether. It is a colorless, water- miscible organic liquid with low viscosity. It is ...

, ScCl₃ yields the

adduct In chemistry, an adduct (; alternatively, a contraction of "addition product") is a product of a direct addition of two or more distinct molecules, resulting in a single reaction product containing all atoms of all components. The resultant is ...

ScCl₃(THF)₃ as white crystals. This THF-soluble complex is used in the synthesis of organoscandium compounds. ScCl₃ has been converted to its dodecyl sulfate salt, which has been investigated as a "Lewis acid-surfactant combined catalyst" (LASC) in aldol-like reactions.

Reduction

Scandium(III) chloride was used by Fischer et al. who first prepared metallic scandium by

electrolysis In chemistry and manufacturing, electrolysis is a technique that uses Direct current, direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of c ...

of a eutectic melt of scandium(III) chloride and other salts at 700-800 °C. ScCl₃ reacts with scandium metal to give a number of chlorides where scandium has an oxidation state <+3, ScCl, Sc₇Cl₁₀, Sc₂Cl₃, Sc₅Cl₈ and Sc₇Cl₁₂. For example, reduction of ScCl₃ with scandium metal in the presence of

caesium chloride Caesium chloride or cesium chloride is the inorganic compound with the formula Caesium, CsChloride, Cl. This colorless salt is an important source of caesium ions in a variety of niche applications. Its crystal structure forms a major structural ...

gives the compound CsScCl₃ which contain linear chains of composition Sc^IICl₃⁻, containing Sc^IICl₆ octahedra sharing faces.

Uses

Scandium(III) chloride is found in some halide lamps,

optical fiber An optical fiber, or optical fibre, is a flexible glass or plastic fiber that can transmit light from one end to the other. Such fibers find wide usage in fiber-optic communications, where they permit transmission over longer distances and at ...

s, electronic ceramics, and

lasers A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word ''laser'' originated as an acronym for light amplification by stimulated emission of radi ...

.Metal Suppliers Online. (2000)
Scandium Chloride
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References

{{Chlorides Scandium compounds Chlorides Metal halides