Triethylgallium

Triethylgallium is the organogallium compound with the formul Ga(C₂H₅)₃. Also called TEGa, it is a metalorganic source of gallium for metalorganic vapour phase epitaxy (MOVPE) of compound semiconductors. It is a colorless pyrophoric liquid,^[2] typically handled with air-free techniques. It was discovered by Cornell University chemists L. M. Dennis and Winton Patnode in 1931.^[3]

Triethylgallium

Names
IUPAC name triethylgallane
Systematic IUPAC name triethylgallium
Identifiers
CAS Number	1115-99-7
3D model (JSmol)	Interactive image
ChemSpider	59583
ECHA InfoCard	100.012.939
PubChem CID	66198
CompTox Dashboard (EPA)	DTXSID1061497
SMILES CC[Ga](CC)CC
Properties
Chemical formula	C6H15Ga
Molar mass	156.9 g/mol
Appearance	colourless liquid
Melting point	−82.3 °C (−116.1 °F; 190.8 K)
Boiling point	143 °C (289 °F; 416 K)
Solubility in water	Reacts[1]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	pyrophoric
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation and reactions

The main routes involve alkylation of gallium trichloride. When this alkylation is effected with ethyl Grignard reagent in ether, the product is the diethyl ether adduct of triethylgallium. The ether is not easily removed. Thus an alternative route involves transmetalation with triethylaluminium according to this simplified equation:^[4]

GaCl₃ + 3 AlEt₃ → GaEt₃ + 3 AlClEt₂

Triethylgallium readily converts to the air-stable, colorless alkoxide by two routes, oxidation and alcoholysis:^[4]

GaEt₃ + 0.5 O₂ → GaEt₂(OEt)

GaEt₃ + EtOH → GaEt₂(OEt) + EtH

The sweet odor associated with triethylgallium is due to the alkoxide.

Redistribution reactions occur with gallium trichloride:^[4]

2GaEt₃ + GaCl₃ → 3 GaEt₂Cl

Applications

TEGa can be a useful alternative to trimethylgallium in the metalorganic vapour phase epitaxy of compound semiconductors because films grown using TEGa have been shown to have a lower carbon impurity concentration.^[5]

Related compounds

• Trimethylgallium, with similar properties.

References

1. amdg.ece.gatech.edu/msds/mo/teg_epichem.pdf
2. Shenaikhatkhate, D; Goyette, R; Dicarlojr, R; Dripps, G (2004). "Environment, health and safety issues for sources used in MOVPE growth of compound semiconductors". Journal of Crystal Growth. 272 (1–4): 816–821. Bibcode:2004JCrGr.272..816S. doi:10.1016/j.jcrysgro.2004.09.007.
3. Dennis, L. M.; Patnode, Winton (January 1932). "GALLIUM TRIETHYL MONOETHERATE, GALLIUM TRIETHYL, GALLIUM TRIETHYL AMMINE¹". Journal of the American Chemical Society. 54 (1): 182–188. doi:10.1021/ja01340a024. ISSN 0002-7863.
4. J.J.Eisch, R. B. King, ed. (1981). Organometallic Syntheses Volume 2. Nontransition Metal Compounds. NY, NY: Academic Press.
5. Saxler, A; Walker, D; Kung, P; Zhang, X; Razeghi, M; Solomon, J; Mitchel, W; Vydyanath, H (1997). "Comparison of trimethylgallium and triethylgallium for the growth of GaN". Applied Physics Letters. 71 (22): 3272–3274. Bibcode:1997ApPhL..71.3272S. doi:10.1063/1.120310.