Copper-Rich Framework Selenoarsenates Based on Icosahedral Cu8Se13 Clusters

Three copper‐rich framework selenoarsenates, (H2en)1.5[Cu8(μ8‐Se)(AsSe4)6/2] (1), (H2dap)1.5[Cu8(μ8‐Se)(AsSe4)6/2] (2), and Na2(H2dap)0.5[Cu8(μ8‐Se)(AsSe4)6/2] (3), were synthesized under solvothermal conditions. These three compounds are isostructural and contain a 3D Cu‐As‐Se framework constructed from novel icosahedral Cu8Se13 clusters linked by As5+, with counterions located in the cavities. The icosahedral Cu8Se13 clusters represent the first icosahedral Cu‐Se unit found in 3D framework chalcogenides, and contain an unusual μ8‐cubic bridging Se2– ion at the core site. The covalent 3D Cu‐As‐Se framework is rigid and not sensitive to the shape and charge density of counterions.