RESUMEN
The inter-action between 8-hy-droxy-quinoline (8HQ, C9H7NO) and naphthalene-1,5-di-sulfonic acid (H2NDS, C10H8O6S2) in aqueous media results in the formation of the salt hydrate bis-(8-hy-droxy-quinolinium) naphthalene-1,5-di-sulfonate tetra-hydrate, 2C9H8NO+·C10H6O6S2 2-·4H2O. The asymmetric unit comprises one protonated 8HQ+ cation, half of an NDS2- dianion symmetrically disposed around a center of inversion, and two water mol-ecules. Within the crystal structure, these components are organized into chains along the [010] and [10] directions through O-Hâ¯O and N-Hâ¯O hydrogen-bonding inter-actions, forming a di-periodic network parallel to (101). Additional stabilizing inter-actions such as C-Hâ¯O, C-Hâ¯π, and π-π inter-actions extend this arrangement into a tri-periodic network structure.