A ₂ Se ₂ C ₂ (A = Na–Cs): crystalline compounds featuring ⁻ Se–CC–Se ⁻ dianions with short-range structural disorder

The crystal structures of A 2 Se 2 C 2 (A = Na–Cs) with an unusual local disorder of − Se–CC–Se − anions were solved by a combination of conventional IR/Raman and Rietveld analyses, DFT calculations, and total scattering data (pair distribution function).