Cs2Cr4O13: a new structure type among alkali tetrachromates

Dicaesium tetrachromium(VI) tridecaoxide, Cs₂Cr₄O₁₃, contains finite Cr₄O₁₃]²⁻ anions composed of four corner‐linked CrO₄ tetrahedra. These anions are linked by Cs⁺ cations whose Cs—O bond lengths range between 3.015 (2) and ∼3.7 Å. Although Cs₂Cr₄O₁₃ is not isotypic with its NH₄, K or Rb analogs, the Cr₄O₁₃]²⁻ anions in all these compounds exhibit a similar zigzag‐like geometry.