Cu3V10O28·24H2O and CuNa4V10O28·23H2O

The crystal structures of tricopper decavanadate tetracosa­hydrate, (I), and copper tetra­sodium decavanadate tricosa­hydrate, (II), have been determined by single‐crystal X‐ray diffraction. Both compounds exhibit a catenary structure consisting of [V10O28]6− anions linked by Cu2+ cations in (I) or by Na+ cations in (II). Compound (II) also contains a polymeric linear array of edge‐sharing [Na(OH2)6]+ and [Cu(OH2)6]2+ octahedra. In both compounds, the [V10O28]6− ions lie about inversion centres and the Cu2+ ions in (I) also lie about inversion centers.