Relative acceptor strength of gallium trihalides towards oxygen and sulphur donors

Abstract

The nine compounds L,GaX₃ where L is Et₂O, Me₂S, or Et₂S and X is Cl, Br, or I have been prepared, most of them for the first time. Thermochemical data have been obtained on the tribromide and tri-iodide complexes and the results, together with known data on the trichloride complexes, are interpreted in terms of steric and polarisability effects. The donor strength of nitrogen, oxygen, and sulphur towards all three trihalides follows the sequence N > S > O. For each ligand the sequence of acceptor strengths is GaCl₃ > GaBr₃ > Gal₃.