Abstract
The complex of boron trifluoride with benzoic anhydride has been prepared. One molecule of anhydride coordinates three molecules of boron trifluoride. The infrared spectrum shows that coordination takes place at the carbonyl groups, whose frequency is lowered some 200 cm−1. There is no trace of the benzoylium cation, C6H5O+. Although the spectra are complex, tentative assignments are made.