The cocrystal nicotinamide-succinic acid (2/1)

In the asymmetric unit of the crystal structure of nicotinamide–succinic acid (2/1), 2C6H6N2O·C4H6O4, there are two independent nicotinamide molecules in general positions and two half succinic acid molecules which lie about inversion centres. The structure contains acid–pyridine and amide–amide synthons with nicotinamide molecules forming ladders of alternating R22(8) and R42(8) rings linked through succinic acid to generate a corrugated hydrogen‐bonded sheet. This sheet is a common supramolecular unit found in other 2:1 nicotinamide–dicarboxylic acid cocrystals, but the presence of two crystallographically distinct nicotinamides with anti and syn conformations, forming two distinct sheets within the same structure, is a novel packing feature in this type of material.