In the organic cation of the title salt, the cyclo­hexane ring is in chair conformation with the two methyl­ammonium substituents in the equatorial positions. The crystal structure features extensive hydrogen-bonding inter­actions.

The synthesis of p-toluidinium perchlorate (systematic name: 4-methylanilinium perchlorate), C7H10N+·ClO4 −, was carried out from an aqueous reaction of perchloric acid with p-toluidine. This compound was characterized by powder XRD, IR and UV–Vis spectroscopy. The structure was further confirmed by a single-crystal X-ray diffraction study. The crystal structure is formed by a succession of two-dimensional molecular layers consisting of perchlorate anions and organic cations parallel to the (100) plane and located at x = 2n + ½ (n ∈ Z). Each mixed layer is formed by infinite chains {C7H10N+·ClO4 −} n parallel to the [010] direction and developing along the c axis, generating R 2 4(8), R 2 2(4) and R 4 4(12) graph-set motifs. The results of a theoretical study using the DFT method at the B3LYP/6–311++G(d,p) level are in good agreement with the experimental data. Hirshfeld surface and fingerprint plots reveal that the structure is dominated by O...H/H...O (54.2%), H...H (26.9%) and C—H ...π (14.3%) contacts. The studied crystal was refined as a two-component twin