Abstract
The asymmetric unit of the title compound, C10H24N3+center dot-0.5C(4)H(2)O(4)(2-)center dot 0.5C(4)H(4)O(4), comprises a triisopropylguanidinium cation, half of a fumarate dianion and half of a fumaric acid molecule; both the fumarate dianion and the fumaric acid molecule are located on inversion centres. In the crystal, intermolecular O-H center dot center dot center dot O hydrogen bonds between the carboxyl groups of the fumaric acid molecules and the carboxylate groups of the fumarate anions lead to the formation of a hydrogen-bonded supramolecular twisted chain along the b axis. The triisopropylguanidinium cations interact with the fumarate-fumaric acid chains via extensive N-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds, leading to a ladder arrangement, with the cation being the rungs that bridge three curled chains of fumarate-fumaric acid. The crystal packing is stabilized by N-H center dot center dot center dot O and C-H center dot center dot center dot O (cation center dot center dot center dot fumarate/fumaric) and O-H center dot center dot center dot O (fumarate center dot center dot center dot fumaric) hydrogen bonds, consolidating a three-dimensional network.