Creatinium hydrogen oxalate

The crystal structure of the title compound, C₄H₁₀N₃O₂⁺·C₂HO₄⁻, is stabilized by N—H...O and O—H...O hydrogen bonds. The anions are connected by an O—H...O hydrogen bond, leading to C(5) chain extending along c axis. The cations are dimerized around the corners of the unit cell, leading to an R₂²(14) ring motif. This leads to a cationic mol­ecular aggregation at x = 0 or 1 and an anionic mol­ecular aggregation at x = 1/2.

Creatininium 2-chloro­acetate

In the title compound (systematic name: 2-amino-1-methyl-4-oxo-4,5-dihydro-1H-imidazol-3-ium 2-chloro­acetate), C₄H₈N₃O⁺·C₂H₂ClO₂⁻, the mol­ecular aggregations are stabil­ized through classical (N—H...O) and non-classical (C—H...O and C—H...N) hydrogen-bonding inter­actions. The cations are linked to the anions, forming ion pairs through two N—H...O bonds that produce characteristic R₂²(8) ring motifs. These cation–anion pairs are connected through another N—H...O hydrogen bond, leading to an R₄²(8) ring motif. Further weak C—H...N inter­actions link the mol­ecules along the a axis, while other C—H...O inter­actions generate zigzag chains extending along b.