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.