The reaction of (CH3)(3)Ga with NH(CH2CH3)(2) led to the formation of trimethylgallium diethylamine, (CH3)(3)(GaNH)-N-.(CH2CH3)(2), The structure of (CH3)(3)(GaNH)-N-.(CH2CH3)(2) was detennined from gas-phase electron-diffraction data combined with results from ab initio molecular orbital and density functional theory calculations. A gauche-anti conformer was found where the two Ga-N-C-C torsional angles are phi(1) = 151(4)degrees and phi(2) = -100(4)degrees. The average experimental bond distances (r(g)) and bond angles (angle(alpha)), with estimated 2sigma uncertainties (sigma include estimates of systematic errors and correlation in the experimental data) are r(C-H) 1.116(3) Angstrom, r(Ga-C) = 1.996(3) Angstrom, r(Ga-N) = 2,204(12) Angstrom, r(C-N) = 1.474(4) Angstrom, r(C-C) = 1.544(4) Angstrom angleN-Ga-C = 99.5(13)degrees, ZGa-N-C = 112.5(9)degrees, angleN-C-C = 114.8(8)degrees, angleC-N-C = 113.3(11)degrees, and angleC-Ga-C = 117.3(7)degrees. Thermolysis of (CH3)(3)(GaNH)-N-.(CH2CH3)(2) was studied, from which it was concluded that the compound is not a suitable precursor for the production of GaN in MOCVD.