Bis(2-amino-5-methylpyridinium) fumarate–fumaric acid (1/1)

Abstract

In the crystal structure of the title compound, C6H9N2+·0.5C4H2O42−·0.5C4H6O4, the fumarate dianion and fumaric acid molecule are located on inversion centres. The 2-amino-5-methylpyrimidinium cation interacts with the carboxylate group of the fumarate anion through a pair of N—H...O hydrogen bonds, forming an R22(8) ring motif. These motifs are centrosymmetrically paired via N—H...O hydrogen bonds, forming a complementary DDAA array. The carboxyl groups of the fumaric acid molecules and the carboxylate groups of the fumarate anions are hydrogen bonded through O—H...O hydrogen bonds, leading to a supramolecular chain along [101]. The crystal structure is further stabilized by weak C—H...O hydrogen bonds.