Crystal structure and Hirshfeld surface analysis of hydro-nium 3,5-di-carb-oxy-benzene-sulfonate trihydrate.

The title com-pound, hydro-nium 3,5-di-carb-oxy-benzene-sulfonate trihydrate, H3O+·C8H5O7S-·3H2O, crystallizes in the triclinic space group P with one mol-ecule in the asymmetric unit. The structure is the pseudopolymorph with an additional three water mol-ecules to known hydro-nium 3,5-dicarb-oxybenzene-sulfonate. The 3,5-dicarb-oxybenzene-sulfonate (SIP-) moiety is surrounded by nine mol-ecules, i.e. three SIP- anions, five water mol-ecules and one oxonium ion. The structure, containing a hy-dro-gen-bonded water cluster with eight mol-ecules, forms an R 8 6(16) ring motif through inter-molecular hy-dro-gen bonding.