Bis(tetramethylamonium) bis-(2,4,5-carboxybenzoate)-benzene-1,2,4,5- tetracarboxylic acid (1/1)

Abstract

The asymmetric unit of the title compound, 2C4H12N+· 2C10H5O8 -·C10H6O8, consists of a tetra-methyl-amonium cation, an anion derived from the singly deprotonated pyromellitic acid anion, 2,4,5-carboxy-benzoate (H3bta-), and one-half of a benzene-1,2,4,5-tetra-carboxylic acid (H4bta) mol-ecule, which has the centroid of the aromatic ring positioned at a crystallographic centre of inversion. The H4bta and H3bta- residues are involved in an extensive inter-molecular O - H⋯O hydrogen-bonding network, which leads to a three-dimensional supra-molecular structure containing one-dimensional channels running parallel to the [001] crystallographic direction. These channels house the tetra-methyl-amonium cations. © International Union of Crystallography 2008.