Anthracene-1,8-dicarboxylic acid

Anthracene-1,8-dicarboxylic acid, C16H10O4, crystallized in the noncentrosymmetric space group P2(1)2(1)2(1). The carboxyl H and O atoms are ordered, The carboxyl groups make angles of 13.9(2) and 21.6(2)degrees with the best-fit core plane and the average distance of the core atoms from this plane is 0.018(12) Angstrom. The anthracene core displays near twofold symmetry. Each molecule is involved in cyclic-dimer hydrogen bonding with two other molecules so as to form zigzag chains of hydrogen-bonded molecules which are not cross-linked with one another. These discrete chains are separated from each other by C ... C, C ... H and H ... H closest approaches.