(15-Crown-5)caesium Dicopper(I) Triiodide, (15-Crown-5)potassium Dicopper(I) Triiodide and (15-Crown-5)rubidium Dicopper(I) Triiodide

(15-Crown-5)caesium triiododicopper(I), [Cs(C₁₀H₂₀O₅)][Cu₂I₃], (15-crown-5)potassium triiododicopper(I), [K(C₁₀H₂₀O₅)][Cu₂I₃], and (15-crown-5) rubidium triiododicopper(I), [Rb(C₁₀H₂₀O₅)][Cu₂I₃], are isostructural. They contain a polymeric Cu₂I₃^-1 moiety, catena-poly[[copper(I)-₂-iodo-copper(I)]-di-₃-iodo], which may be viewed as a series of opposite edge sharing Cu₂I₂ rhombs, with alternate units bridged by an additional I atom in an up, up, down, down pattern.