organic compounds
Open access
The asymmetric unit of the title compound, 2C10H18N+·HPO42−·1.5C4H4O4, contains two adamantan-1-aminium cations, one hydrogen phosphate anion, and one and a half molecules of fumaric acid, one of which exhibits crystallographic inversion symmetry. Each HPO42− anion is hydrogen bonded, via all of its O atoms, to four NH3+ groups of the adamantan-1-aminium cations, forming chains along [100]. These chains are, in turn, interconnected via a set of O—HO hydrogen bonds involving the fumaric acid solvent molecules, forming layers parallel to (001). Weak C—HO interactions lead to a consolidation of the three-dimensional set-up.
organic compounds
Open access
In the crystal structure of the title molecular salt, 3C2H5N4+·HPO42−·H2PO4−·3H2O, the phosphate-based framework is built upon layers parallel to (010) made up from the H2PO4− and HPO42− anions and water molecules, which are interconnected through O—HO hydrogen bonds. The organic cations are located between the phosphate–water layers and are connected to them via N—HO hydrogen bonds. The bond-length features are consistent with an imino resonance form for the exocyclic amino group, as is commonly found for a C—N single bond involving sp2-hybridized C and N atoms.