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

In the title compound, C(21)H(16)O(2), 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.