Synthesis, structure, and characterization of a novel selenidoarsenate: Incorporation of [Mn(phen)2]2 + cations into ∞1[AsIII2Se3(Se2)]2 − chains

► A novel compound, [Mn(1,10′-phen)2]n[AsIII2Se3(Se2)]n1, has been synthesized. ► Compound 1 has the rare 1 ∞[AsIII2Se3(Se2)]2 − chains. ► Compound 1 exhibits semiconducting properties. ► Compound 1 shows the antiferromagnetic interaction between Mn2 + ions.