2-[(2-Acet-oxy-benzo-yl)-oxy]benzoic acid.
The title compound, C(16)H(12)O(6), is a common impurity of ortho-acetyl-salicylic acid (aspirin). The benzene rings form a dihedral angle of 81.9 (1)° while the acetyl and carboxyl groups form dihedral angles of 74.0 (1) and 26.4 (2)°, respectively, with the benzene rings to which they are bound. In the crystal, mol-ecules are linked by pairs of O-H⋯O hydrogen bonds between the carboxyl groups, forming inversion dimers.
University of Southern Denmark, Department of Physics, Chemistry and Pharmacy, Campusvej 55, 5230 Odense,  Denmark.
Katarzyna A
KA
Solanko
Andrew D
AD
Bond