Acta Cryst. (2006). E62, o1170-o1172  [ doi:10.1107/S1600536806005812 ]

Pamoic acid determined from powder diffraction data

D. A. Haynes, J. Van de Streek, J. C. Burley, W. Jones and W. D. S. Motherwell

Abstract: The title compound [systematic name: 4,4'-methylenebis(3-hydroxy-2-naphthoic acid)], C₂₃H₁₆O₆, has one half-molecule in the asymmetric unit. The molecular twofold rotational axis about the central C atom is preserved on crystallization. A chain formed by R₂²(8) hydrogen bonds runs along the c axis and an intramolecular O-HO=C-OH hydrogen bond is also formed. The crystal structure was solved by simulated annealing from laboratory X-ray powder diffraction data, with data collected at room temperature. Rietveld refinement of this model led to a final R_wp value of 0.0391 at 1.39 Å resolution.

Online 28 February 2006

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