<p>The paper systematizes and discusses the structures of uranyl tetrachloride complexes with inorganic and protonated organic cations, which were investigated by single-crystal X-ray structure analysis. The crystallochemical structural features of the analyzed compounds were determined. In the studied crystal structures of the UO₂²⁺ tetrachloride complexes, the coordination polyhedron of the hexavalent uranium atom has a tetragonal-bipyramidal (flattened octahedral) structure with the oxygen atoms of the uranyl group located at the apical vertices of the tetragonal-bipyramidal polyhedron. In the presence of free Cl⁻ ions and/or free neutral molecules containing acceptor atoms in the structures of the uranyl tetrachloride complexes that are not bound to the U atom, the cations do not interact with the donor Cl atoms of the anion, but form hydrogen bonds with free chlorine ions and acceptor atoms of free molecules.</p>