Comment on ‘A simple method for the matrix isolation of monomeric and dimeric carboxylic acids’. Possible implications of findings, in regard to liquid formic acid

Abstract

It is suggested that the infrared bands due to a minor species of formic acid (denoted as ‘X’) observed by Halupka and Sander in Ar matrices at 7–10 K, following trapping from a supersonic cold gaseous jet, are due not to higher aggregates but to an open-chain (HCO 2H) 2 species with an energetically favourable arrangement of the two CO dipoles. This species is probably present, as a minor component, also in liquid formic acid.