RETRACTED: Oxonium picrate (Retracted article. See vol. 67, pg. E16, 2011)

The title compound, H3O+center dot C6H2N3O7-, consists of one picrate anion and one oxonium cation. The oxonium cation is located on a crystallographic twofold axis and both its H atoms are disordered, each over two symmetry-equivalent positions with occupancy ratios of 0.75. The picrate anions are also located on twofold axes bisecting the phenolate and p-nitro groups. pi-pi interactions between the rings of the picrates [centroid-to-centroid distances of 3.324 (2) angstrom] connect the anions to form stacks along the a-axis direction. The stacks are further joined together by the protonated water molecules through hydrogen bonds to form two-dimensional sheets extending parallel to the ab plane. The sheets are stacked on top of each other along the c-axis direction and connected through C-H center dot center dot center dot O interactions between the CH groups of the benzene rings and the picrate nitro groups, with C center dot center dot center dot O distances of 3.450 (2) angstrom.