scandium triiodide

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| IUPACName = Scandium triiodide

| OtherNames = Scandium(III) iodide
Scandium(3+) triiodide
Triiodoscandium

|Section1={{Chembox Identifiers

| CASNo = 14474-33-0

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| UNII = QVJ18SK04T

| PubChem = 4420285

| EC_number = 238-469-0

| InChI = InChI=1S/3HI.Sc/h3*1H;/q;;;+3/p-3

| InChIKey = HUIHCQPFSRNMNM-UHFFFAOYSA-K

| SMILES = [Sc](I)(I)I

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|Section2={{Chembox Properties

| Formula = ScI₃

| MolarMass = 425.66

| Appearance = Yellowish solid

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| MeltingPtC = 920

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|Section3={{Chembox Hazards

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| Section9 = {{Chembox Related

| OtherAnions = Scandium fluoride
Scandium chloride
Scandium bromide

| OtherCations = Yttrium(III) iodide
Lutetium(III) iodide

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Scandium triiodide, also known as scandium iodide, is an inorganic compound with the formula ScI₃ and is classified as a lanthanide iodide. This salt is a yellowish powder.Haeberle, N., 1973, Preparation of highly pure lanthanide iodides, Technisch-Wissenschaftliche Abhandlungen der Osram-Gesellschaft, v. 11, p. 285 It is used in metal halide lamps together with similar compounds, such as caesium iodide, because of their ability to maximize emission of UV and to prolong bulb life. The maximized UV emission can be tuned to a range that can initiate photopolymerizations.Brabham, D.E., Metal halide lamp for curing adhesives. U.S. Patent 6,888,312, March 1, 2011

Scandium triiodide adopts a structure similar to that of iron trichloride (FeCl₃), crystallizing into a rhombohedral lattice. Scandium has a coordination number of 6, while iodine has a coordination number of 3 and is trigonal pyramidal.Men'kov, A. A., Komissarova, L. N., 1964, X-ray study of scandium iodide, Zhurnal Neorganicheskoi Khimii, v. 9, p. 766

The purest scandium triiodide is obtained through direct reaction of the elements:

: 2 Sc + 3 I₂ → 2 ScI₃

Alternatively, but less effectively, one can produce anhydrous scandium triiodide by dehydrating ScI₃(H₂O)₆.