The structure of cyclohexane-1, 3cis, 5cis-tricarboxylic acid, determined from powder X-ray diffraction data

The previously unknown crystal structure of cyclohexane-1, 3cis, 5cis-tricarboxylic acid (CTA) has been solved from laboratory X-ray powder diffraction data using a simulated annealing algorithm followed by restrained Rietveld refinement (reduced-χ²=8.531 for the refined crystal structure). The structure is triclinic $\text{(}\text{P}\text{1}\text{̄}\text{,}\text{Z=4}\text{).}$ Five out of six of the CO₂H groups in the asymmetric unit form R₂²(8) hydrogen bond motifs with neighbouring CO₂H groups. The motifs connect molecules to form pseudo-hexagonal, ten-molecule rings that fuse into supramolecular buckled honeycomb sheets, which stack and are linked by O–H⋯O hydrogen bonds.