A short intramolecular hydrogen bond in the structure of the superacid salt lithium trihydrogen dimalonate

Abstract

Crystals of the title compound are monoclinic, space group P2₁/c, Z= 4, with a= 9.664(2), b= 7.173(1), c= 13.199(5)Å, β= 108.74(3)°. The structure was solved from diffractometer data by direct methods and refined by block-diagonal least-squares techniques to R 0.07(1 939 observed reflections). The carboxy-groups of the planar hydrogen malonate ion are linked by an unsymmetrical and very short [2.481(3)Å] intramolecular hydrogen bond. The malonic acid molecule also is found to be nearly planar. The malonic acid and the hydrogen malonate ion are linked together by two short intermolecular O–H ⋯ O hydrogen bonds [2.655(3) and 2.575(3)Å] and form an infinite chain structure in which the two species alternate. The Li⁺ ions have tetrahedral co-ordination and link the infinite chains.