organic compounds
Pseudopolymorphism in hydroxybenzophenones: the dihydrate of 2,2',4,4'-tetrahydroxybenzophenone
A dihydrate pseudopolymorph of bis(2,4-dihydroxyphenyl)methanone, C13H10O5·2H2O, (I), was obtained during polymorphism screening of hydroxybenzophenone derivatives. This structure, in which the molecule sits on a twofold axis, was compared with the known anhydrous form of (I) [Schlemper (1982). Acta Cryst. B38, 554-559]. The role of water in the crystal assembly was established on the basis of the known monohydrate pseudopolymorph of 3,4-dihydroxybenzophenone [Landre, Souza, Corrêa, Martins & Doriguetto (2010). Acta Cryst. C66, o463-o465].
organic compounds
A racemic crystalline form of terebic acid, C7H10O4, which is an important industrial chemical compound, is reported for the first time. The crystal structure is stabilized by O-HO and C-HO hydrogen bonds which form racemic double layers parallel to (001).