The title compound, C12H11N2+.C2H3O2-.H2O, is a hydrated salt of 2-met
hylperimidinium acetate. The 2-methylperimidinium cations are protonat
ed al the N atoms. In the acetate anions, the C-O bond distances are 1
.238(3) and 1.265(3) Angstrom. A hydrogen-bonding network allows the s
elf assembly of the ionic counterparts, together with the water of hyd
ration, along the c axis.