Ab Initio LCAO–MO–SCF Calculations on Formic Acid, Formate Ion, and Protonated Formic Acid

The site of protonation of formic acid as well as the proton affinities of the formate ion and formic acid have been estimated using ab initio LCAO–MO–SCF calculations with Gaussian basis sets. The three carbonyl protonated formic acid conformers were found to be more stable than the hydroxy protonated isomer for all basis sets. In agreement with experimental observation, the large basis set calculations gave the cis–trans conformer to be the most stable.