Diverse Closed Cavities in Condensed Rare Earth Metal–Chalcogenide Matrixes: Cs[Lu7Q11] and (ClCs6)[RE21Q34] (RE = Dy, Ho; Q = S, Se, Te)

Two types of novel ordered chalcogenids Cs­[Lu7Q11] (Q = S, Se) and (ClCs6)­[RE21Q34] (RE = Dy, Ho; Q = S, Se, Te) were discovered by high-temperature solid state reactions. The structures were characterized by single-crystal X-ray diffraction data. Cs­[Lu7Q11] crystallize in the orthorhombic Cmca (no. 64) with a = 15.228(4)–15.849(7) Å, b = 13.357(3)–13.858(6) Å, c = 18.777(5)–19.509(8) Å, and Z = 8. (ClCs6)­[RE21Q34] crystallize in the monoclinic C2/m (no. 12) with a = 17.127(2)–18.868(2) Å, b = 19.489(2)–21.578(9) Å, c = 12.988(9)–14.356(2) Å, β = 128.604(2)–128.738(4)°, and Z = 2. Both types of compounds feature 3D RE–Q network structures that embed with dual tricapped cubes Cs2@Se18 in the former or unprecedented matryoshka nesting doll structure cavities of (ClCs6)@Se32 in the latter. The band gap, band structure, as well as a structure change trend of the majority of A/RE/Q compounds are presented.