Acta Cryst. (2004). E60, o1449-o1450  [ doi:10.1107/S1600536804018379 ]

4-Methoxypyridinium betaine of squaric acid

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

Abstract: The title compound, 4-methoxypyridinium-3-squarate or 2-(4-methoxypyridinio)-3,4-dioxocyclobut-1-en-1-olate, C₁₀H₇NO₄, exhibits an interplanar angle of 5.3  (2)°. The bond lengths within the squarate system represent average values for the two possible resonance structures, with a central typical carbonyl bond [1.209  (3)  Å] flanked by two longer `semicarbonyl' bonds of length 1.230  (3)  Å.

Online 31 July 2004

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