π–π Stacking in bis­(quinolinium) tetra­chloro­zincate dihydrate

The asymmetric unit of the title compound, (C₉H₈N)₂[ZnCl₄]·2H₂O, consists of one quinolinium cation, one-half of the [ZnCl₄]²⁻ anion and one water mol­ecule. The geometry around the Zn atom is approximately tetra­hedral, with the Zn atom lying on a twofold axis. The water mol­ecules hydrogen bond to the [ZnCl₄]²⁻ anions and the quinolinium cations, forming a two-dimensional network with the cations protruding on both sides of the network and stacking through π–π inter­actions with adjacent networks.