Antimony triiodide is the

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with the formula Sb I₃. This ruby-red solid is the only characterized "binary"

iodide An iodide ion is the ion I−. Compounds with iodine in formal oxidation state −1 are called iodides. In everyday life, iodide is most commonly encountered as a component of iodized salt, which many governments mandate. Worldwide, iodine de ...

antimony Antimony is a chemical element with the symbol Sb (from la, stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient ti ...

, i.e. the sole compound isolated with the formula Sb_xI_y. It contains antimony in its +3 oxidation state. Like many iodides of the heavier

main group element In chemistry and atomic physics, the main group is the group of elements (sometimes called the representative elements) whose lightest members are represented by helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, and fluorine as arran ...

s, its structure depends on the phase. Gaseous SbI₃ is a molecular, pyramidal species as anticipated by

VSEPR theory Valence shell electron pair repulsion (VSEPR) theory ( , ), is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms. It is also named the Gillespie-Nyholm the ...

. In the solid state, however, the Sb center is surrounded by an

octahedron In geometry, an octahedron (plural: octahedra, octahedrons) is a polyhedron with eight faces. The term is most commonly used to refer to the regular octahedron, a Platonic solid composed of eight equilateral triangles, four of which meet at ea ...

of six iodide ligands, three of which are closer and three more distant. For the related compound BiI₃, all six Bi—I distances are equal.

Production

It may be formed by the reaction of

with elemental

iodine Iodine is a chemical element with the Symbol (chemistry), symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , ...

, or the reaction of

antimony trioxide Antimony(III) oxide is the inorganic compound with the formula Sb2O3. It is the most important commercial compound of antimony. It is found in nature as the minerals valentinite and senarmontite. Like most polymeric oxides, Sb2O3 dissolves i ...

with

hydroiodic acid Hydroiodic acid (or hydriodic acid) is an aqueous solution of hydrogen iodide (HI). It is a strong acid, one that is ionized completely in an aqueous solution. It is colorless. Concentrated solutions are usually 48% to 57% HI. Reactions Hy ...

. Alternatively, it may be prepared by the interaction of antimony and iodine in boiling

benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms ...

tetrachloroethane Tetrachloroethane may refer to either of two isomeric chemical compounds: * 1,1,1,2-Tetrachloroethane (R-130a) * 1,1,2,2-Tetrachloroethane (R-130) See also * Tetrachloroethene * Trichloroethane * Tetrafluoroethane * Tetrabromoethane Tetrabrom ...

Uses

SbI₃ has been used as a dopant in the preparation of thermoelectric materials.

References

External links

Iodides Metal halides Antimony(III) compounds {{inorganic-compound-stub