Article · Wikipedia archive · Last revised Jul 18, 2026

Gallium(III) iodide

Gallium(III) iodide is the inorganic compound with the formula GaI3. A yellow hygroscopic solid, it is the most common iodide of gallium. In the chemical vapor transport method of growing crystals of gallium arsenide uses iodine as the transport agent. In the solid state, it exists as the dimer Ga2I6, with a diborane structure. When vaporized, its forms GaI3 molecules of D3h symmetry where the Ga–I distance is 2.458 Angstroms.

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Gallium(III) iodide
Gallium(III) iodide
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Names
Other names
gallium triiodide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.033.269
EC Number
  • 236-611-6
  • InChI=1S/Ga.3HI/h;3*1H/q+3;;;/p-3 checkY
    Key: DWRNSCDYNYYYHT-UHFFFAOYSA-K checkY
  • InChI=1/Ga.3HI/h;3*1H/q+3;;;/p-3
    Key: DWRNSCDYNYYYHT-DFZHHIFOAW
  • I[Ga](I)I
Properties
GaI3
Molar mass 450.436 g/mol
Appearance light yellow powder
Density 4.5 g/cm31
Melting point 212 °C (414 °F; 485 K)1
Boiling point 340 °C (644 °F; 613 K)1
decomposes
−149.0·10−6 cm3/mol
Thermochemistry2
100 J/(mol·K)
205.0 J/(mol·K)
−238.9 kJ/mol
Hazards
GHS labelling:
GHS05: CorrosiveGHS07: Exclamation markGHS08: Health hazard
Danger
H314, H317, H334, H335, H361
P280, P305+P351+P338, P310
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 0: Will not burn. E.g. waterInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Gallium(III) iodide is the inorganic compound with the formula GaI3. A yellow hygroscopic solid, it is the most common iodide of gallium.3 In the chemical vapor transport method of growing crystals of gallium arsenide uses iodine as the transport agent. In the solid state, it exists as the dimer Ga2I6, with a diborane structure.4 When vaporized, its forms GaI3 molecules of D3h symmetry where the Ga–I distance is 2.458 Angstroms.5

Gallium triiodide can be reduced with gallium metal to give a green-colored gallium(I) iodide. The nature of this species is unclear, but it is useful for the preparation of gallium(I) and gallium(II) compounds.67

Gallium triiodide is a lewis acid, readily reacting with iodides to form the [GaI₄]⁻ anion.

Gallium triiodide needs to be prepared under anhydrous conditions because it reacts with water to form gallium hydroxide and hydrogen iodide:

GaI₃ + 3H₂O → Ga(OH)₃ + 3HI

See also

See also

References

References

  1. Haynes, p. 4.63
  2. Haynes, p. 5.20
  3. Donges, E. (1963). "Gallium(III) Iodide". In Brauer, G. (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 1. NY, NY: Academic Press. p. 846.
  4. Brünig, C.; Locmelis, S.; Milke, E.; Binnewies, M. (2006). "Chemischer Transport fester Lösungen. 27. Mischphasenbildung und chemischer Transport im System Zn Se/Ga As". Zeitschrift für Anorganische und Allgemeine Chemie. 632 (6): 1067–1072. doi:10.1002/zaac.200600008.
  5. Haynes, p. 9.23
  6. Baker, Robert J.; Jones, Cameron (2005). ""GaI": A versatile reagent for the synthetic chemist". Dalton Trans (8): 1341–1348. doi:10.1039/b501310k. hdl:2262/69572. PMID 15824768.
  7. Green, Shaun P.; Jones, Cameron; Stasch, Andreas; Rose, Richard P. (2007). "'GaI': A new reagent for chemo- and diastereoselective C–C bond forming reactions". New J. Chem. 31: 127–134. doi:10.1039/b613669a.

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