The cocrystal nicotinamide-succinic acid (2/1)

In the asymmetric unit of the crystal structure of nicotinamide-succinic acid (2/1), 2C(6)H(6)N(2)O center dot 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 R (2) 2(8) and R (4) 2(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.