4-Nitro­phenyl­hydrazinium picrate monohydrate

In the crystal structure of the title compound, C₆H₈N₃O₂⁺·C₆H₂N₃O₇⁻·H₂O, N—H...O and O—H...O hydrogen bonds link the components into a two-dimensional network parallel to (010). In addition, there are pairs of weak inversion-related C—H...O hydrogen bonds within the two-dimensional network. The three nitro groups are twisted by 1.6 (3), 7.8 (3) and 12.1 (3)° from the ring plane in the anion, while in the cation, the nitro group makes a dihedral angle of 4.6 (2)° with the ring.

Crystal structure of tetraaquabis(8-chloro-9,10-dioxo-9,10-dihydroanthracene-1-carboxyl­ato-κO¹)cobalt(II) dihydrate

In the title complex, [Co(C₁₅H₆ClO₄)₂(H₂O)₄]·2H₂O, the Co^II ion is bound by two carboxylate O atoms of two 5-chloro-9,10-anthra­quinone-1-carboxyl­ate anions and four water O atoms in a trans conformation, forming an irregular octa­hedral coordination geometry. This arrangement is stabilized by intra­molecular O—H...O hydrogen bonds between water and carboxyl­ate. Further O—H...O hydrogen bonds between coordinating and non-coordinating water and carboxyl­ate produce layers of mol­ecules that extend parallel to (001). The organic ligands project above and below the plane. Those ligands of adjacent planes are inter­digitated and there are π–π inter­actions between them with centroid–centroid distances of 3.552 (2) and 3.767 (2) Å that generate a three-dimensional supra­molecular structure.