Triphenylmethyl derivatives, Ph3CX, where X = F, Cl, OH, or OCH3, react with 2 or more moles of boron fluoride to form Ph3CB2F7. Reactions take place rapidly and completely at low temperatures, except in the case of X = OCH3, where cleavage of the ether requires about 1 h at −30 °C. When X = Cl the other product is [Formula: see text]; for OH and OCH3 the products are B(OH)3 and B(OCH3)3·2BF3. The [Formula: see text] ion appears to be more stable than the [Formula: see text] or [Formula: see text] ions.