A new polymorph of bis­(2-amino­pyridinium) fumarate–fumaric acid (1/1) from powder X-ray diffraction

A new polymorph of bis(2-aminopyridinium) fumarate–fumaric acid (1/1), determined using powder X-ray diffraction data, is described. The similarities and differences in hydrogen bonds between the new and previous polymorph are discussed in order to understand the polymorphism of the title salt.