Antimony triiodide

Names IUPAC name Systematic IUPAC name Identifiers ChemSpider ECHA InfoCard 100.029.278 Edit this at Wikidata EC Number UNII Properties I₃Sb Molar mass 502.473 g·mol⁻¹ Appearance red crystals Density 4.921 g/cm³ Melting point 170.5 °C (338.9 °F; 443.6 K) Boiling point 401.6 °C (754.9 °F; 674.8 K) soluble, partially hydrolyses Solubility soluble in benzene, alcohol, acetone, CS₂, HCl, KI, SnCl₄, C₂H₇N
,HI,alkali metal triiodides

insoluble in CHCl3, CCl4 [1] 

Solubility in diiodomethane 10.15% v/v (12 °C)^[2] -147.0·10⁻⁶ cm³/mol Structure Rhombohedral, hR24, R-3, No. 148 1.58 D Thermochemistry 81.6 J/mol·K (gas)^[1] -100.4 kJ/mol^[1] Hazards GHS labelling:^[4] GHS07: Exclamation mark GHS09: Environmental hazard Warning H302, H332, H411 P273 NIOSH (US health exposure limits): TWA 0.5 mg/m³ (as Sb)^[3] TWA 0.5 mg/m³ (as Sb)^[3]

Antimony triiodide

Antimony triiodide

Antimony triiodide is the chemical compound with the formula Sb I₃. This ruby-red solid is the only characterized "binary" iodide of antimony, 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 elements, its structure depends on the phase. Gaseous SbI₃ is a molecular, pyramidal species as anticipated by VSEPR theory. In the solid state, however, the Sb center is surrounded by an octahedron of six iodide ligands, three of which are closer and three more distant.^[5] For the related compound BiI₃, all six Bi—I distances are equal.^[6]

It may be formed by the reaction of antimony with elemental iodine, or the reaction of antimony trioxide with hydroiodic acid.

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

SbI₃ has been used as a dopant in the preparation of thermoelectric materials.^[7]