3-(4-Biphenyl-1-yl)-3-hydroxy-1-phenylprop-2-en-1-one

In the title compound, C21H16O2, the six crystallographically independent molecules (Z′ = 6) all exist in the enolized form. Strong intramolecular hydrogen bonds are observed: one approximate H-atom-centered O...H...O hydrogen bond, two tautomeric forms O—H...O (three molecules) and O...H—O (two molecules). Only one weak intermolecular C—H...O hydrogen bond between two neighboring molecules is observed in the crystal structure. In addition, eight very weak non-conventional intermolecular C—H...π hydrogen-bonding contacts between molecules are observed