Dirubidium aqua­penta­chloro­chromate(III) and dicaesium aqua­penta­chloro­chromate(III)

The structures of the two novel title compounds, Rb₂CrCl₅(H₂O)], (I), and Cs₂CrCl₅(H₂O)], (II), have been determined by single‐crystal X‐ray diffraction. Compounds (I) and (II) crystallize with Pnma and Cmcm symmetry, respectively. In (I), the Cr, three Cl and water O atom lie on a mirror plane; in (II), the Cs, Cr, O and one of the Cl atoms are at sites with m2m symmetry. The chromate anions are in a pseudo‐cubic environment of eight Rb⁺ cations in (I) and in a pseudo‐octahedral environment of six Cs⁺ cations in (II). The structural arrangement correlates with the r_anion/r_cation radius ratio.