The crystal structure of glutaric and pimelic acid. Alternation of properties in the series of dicarboxylic acids

Abstract

Abstract Glutaric acid and pimelic acid have analogous crystal structures. The CH 2 chains are stretched along the c‐axis, the plane of the zigzag is nearly parallel to (100). Packing of the COOH groups is practically identical to that in adipic acid. This packing enforces a torsion in the molecules of the odd acids as a result of their axial symmetry. This torsion may well be the cause of the higher energy content of the odd dicarboxylic acids; an estimate of the torsion energy is made and is shown to be of the right order of magnitude.