Syntheses, Crystal Structures, and Optical and Magnetic Properties of Some CsLnCoQ₃ Compounds (Ln = Tm and Yb, Q = S; Ln = Ho and Yb, Q = Se)

Abstract

Abstract The four new compounds CsTmCoS 3 , CsYbCoS 3 , CsHoCoSe 3 , and CsYbCoSe 3 have been synthesized at 1123 K. These black‐colored isostructural compounds crystallize in the KZrCuS 3 structure type with four formula units in space group Cmcm of the orthorhombic system. The structure of these compounds is composed of layers separated by Cs atoms. Because there are no Q–Q bonds, the formal oxidation states of Cs/Ln/Co/Q are 1+/3+/2+/2−, respectively. CsHoCoSe 3 shows paramagnetic behavior with μ eff = 11.9(1) μ B , whereas CsYbCoS 3 displays an antiferromagnetic‐like transition at ∼2.7 K with μ eff = 5.85(1) μ B . Both CsYbCoS 3 and CsYbCoSe 3 exhibit optical band gaps in the near infrared region and broad absorption bands at lower energies.