Preparation, Crystal Structure, Physical Properties and Electronic Band Structure of TlScQ2 (Q = S, Se and Te)

Abstract

AbstractThe title compounds were prepared by reaction of Tl2Q (Q = S, Se and Te) Sc and Q in the temperature range of 200 to 500 °C. The structures of the selenide and the telluride adopt the α‐NaFeO2 type, while TlScS2 crystallizes in the β‐RbScO2 type structure. The space group is $\rm R{\bar 3}\rm m$ for TlScSe2 and TlScTe2 with a = 3.9370(4) Å, c = 23.194(5) Å, and a = 4.2129(4) Å, c = 24.099(3) Å, respectively. The sulphide crystallizes in P63/mmc with a = 3.761(3) Å and c = 14.942(4) Å. The crystal chemical relations between the three chalcogenides are discussed. According to the electrical measurements and the band structure calculations, the compounds are semiconductors or poor metals.