Cs3Se22, a Selenium‐rich Caesium Polyselenide containing Se8 Crowns and $^{3}_{\infty}\rm [Se_{6}^{3-}]$ Anions with Radical Character

Cs₃Se₂₂ can be prepared together with the known compounds Cs₂Sn₂Se₆ and Cs₄Sn₂Se₆ by reacting Cs₂CO₃ and Sn in a CH₃OH/en solution at 120 °C. The presence of CuCl and the macrocyclic ligand 1,10‐dithia‐18‐crown‐6 are essential for product formation. The caesium polyselenide consists of anionic nets that are separated by two layers of discrete Se₈ rings. Within the polymeric anions pairs of Se₃^·− radical anions and Se₃²⁻ anions are linked through secondary interactions.