2,2′-Bipyridinium 5-nitro­isophthalate 5-nitro­isophthalic acid dihydrate

The title compound, C₁₀H₉N₂⁺·C₈H₄NO₆⁻·C₈H₅NO₆·2H₂O, consists of singly protonated 2,2′-bipyridinium cations, 5-nitroisophthalate anions, 5-nitroisophthalic acid and water mol­ecules of crystallization, linked by N—H...O and O—H...O hydrogen bonds. The moieties are linked by multiple hydrogen bonds into an undulating sheet structure.

2,3,5,6-Tetra­methyl­pyrazinium–tri­chloro­acetate–tri­chloro­acetic acid (1/1/1)

In the title adduct, C₈H₁₃N₂⁺·C₂Cl₃O₂⁻·C₂HCl₃O₂, the tetra­methyl­pyrazine mol­ecule is protonated at one of the N atoms and linked to the tri­chloro­acetate anion via an N—H...O hydrogen bond. The tri­chloro­acetate anion is also linked to the tri­chloro­acetic acid mol­ecule via an O—H...O hydrogen bond.

Tetra­methyl­pyrazine–endo-norbornene-cis-5,6-di­carboxyl­ic acid (1/2)

In the title complex, 2C₉H₁₀O₄·C₈H₁₂N₂, there is an inversion centre at the centre of the 2,3,5,6-tetra­methyl­pyrazine mol­ecule, which is linked to two endo-norbornene-cis-5,6-di­carboxyl­ic acid mol­ecules via O—H...N hydrogen bonds. In the crystal structure, O—H...O and O—H...N hydrogen bonds propagate a one-dimensional zigzag chain, which is extended into layers when combined with longer C—H...O hydrogen bonds.

N,N'-Bis{3-cyano-1-[2,6-dichloro-4-(trifluorometh­yl)phen­yl]-1H-pyrazol-5-yl}-1,4-benzene­diamide dimethyl­formamide disolvate

The title compound, C₃₀H₁₂Cl₄F₆N₈O₂·2C₃H₇NO or C₆H₄[CONH-C₃N₂H(CN)-C₆H₂Cl₂CF₃]₂·2HCONMe₂, is a fivecyclic amide with an overall Z shape, each of the five rings being planar.