Potassium hydrogen dichloromaleate-an unexpected case of intermolecular hydrogen bonding

Abstract

The infrared spectrum of solid KHC1₂C₄O₄ has the characteristic features of intermolecularly bonded acid salts of carboxylic acids. The X-ray structure analysis of the crystals belonging to the space group P1̄, revealed two crystallographically different, strong hydrogen bonds of the same O … O distance 2.449(2) $\text{\$}\text{̊}$linking the dichloromaleate units into one-dimensional arrays parallel to the (1 1 1̄) direction. The infrared spectra of the solution of KHC1₂C₄O₄ and of (C₄H₉)₄NHCl₂C₄O₄ indicate intramolecular hydrogen bonding.