Bis(oxotremorine) fumarate bis-(fumaric acid).

The title compound, bis-(oxotremorine) fumarate bis-(fumaric acid) {systematic name: 1-[4-(2-oxopyrrolidin-1-yl)but-2-yn-yl]pyrrolidinium (2 E )-but-2-ene-di-o-ate bis-[(2 E )-but-2-enedioic acid]}, 2C 12 H 19 N 2 O + ·C 4 H 2 O 4 2- ·2C 4 H 4 O 4 , has a single oxotremorine monocation protonated at the pyrrolidine nitro-gen, one fumaric acid mol-ecule and half of a fumarate dianion in the asymmetric unit. The ions and fumaric acid mol-ecules are held together by N-H⋯O and O-H-⋯O hydrogen bonds in 40-membered rings with graph-set notation R 6 6 (40). The fumarate ions join these rings into infinite chains along [001].