Scandium(III) chloride is the

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

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 betwee ...

ScCl₃. It is a white, high-melting

ionic compound In chemistry, an ionic compound is a chemical compound composed of ions held together by electrostatic forces termed ionic bonding. The compound is neutral overall, but consists of positively charged ions called cations and negatively charged i ...

, which is

deliquescent Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance ...

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 In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was understo ...

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

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 complex In chemistry, metal aquo complexes are coordination compounds containing metal ions with only water as a ligand. These complexes are the predominant species in aqueous solutions of many metal salts, such as metal nitrates, sulfates, and perchlorat ...

es. 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 (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 electr ...

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 ma ...

, ScCl₃ yields the

adduct An adduct (from the Latin ''adductus'', "drawn toward" 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 co ...

ScCl₃(THF)₃ as white crystals. This

THF 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 ...

-soluble complex is used in the synthesis of

organoscandium compound Organoscandium chemistry is an area with organometallic compounds focused on compounds with at least one carbon to scandium chemical bond. The interest in organoscandium compounds is mostly academic but motivated by potential practical application ...

s. 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 electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of elements from n ...

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 Cs Cl. This colorless salt is an important source of caesium ions in a variety of niche applications. Its crystal structure forms a major structural type where each ...

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 in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to ...

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" is an acronym for "light amplification by stimulated emission of radiation". The fir ...

.Metal Suppliers Online. (2000)
Scandium Chloride
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References

{{Chlorides Scandium compounds Chlorides Metal halides