Acta Cryst. (2005). E61, o1090-o1092  [ doi:10.1107/S1600536805008457 ]

4-Phenylpyridinium betaine of squaric acid

T. Kolev, R. Wortmann, M. Spiteller, W. S. Sheldrick and H. Mayer-Figge

Abstract: The title compound, 4-phenylpyridinium-3-squarate, C₁₅H₉NO₃, exhibits an interplanar angle between the pyridinium and squarate rings of 0.6 (1)°. It displays a dipolar electronic ground-state structure, with a positively charged pyridinium fragment and a negatively charged squarate moiety. In the molecule, the two aromatic rings are twisted by 31.6 (1)°. The bond lengths within the squarate system represent average values for the two possible resonance structures, with a central typical carbonyl bond [1.203 (2) Å] flanked by two longer `semicarbonyl' bonds of lengths 1.228 (2) and 1.221 (2) Å.

Online 25 March 2005

Copyright © International Union of Crystallography
IUCr Webmaster