Synthesis, Crystal Structure, and Optical Property of Ce4InSbS9

Abstract

Quaternary sulfide Ce₄InSbS₉ is prepared at 1223 K in an evacuated silica tube. It crystallizes in the chiral tetragonal space group P4₁2₁2 (No. 92) with a = 10.1961(3) Å, c = 28.128(2) Å, V = 2924.2(2) ų, D_calc = 4.932 g/cm³, and Z = 8. The structure features infinite 2₁ helical chains [In₂Sb₂S₁₁¹⁰⁻]_∞ propagating along the c direction separated by Ce³⁺ cations and S²⁻ anions. The UV/Vis diffuse reflectance spectroscopy study shows that the optical gap of Ce₄InSbS₉ is about 2.07 eV, showing a red shift with respect to corresponding sulfide La₄InSbS₉, which is attributed to the allowed electronic transfer from the narrow Ce4f level to the conduction band, mainly built from empty Ce5d orbitals. The magnetic susceptibility measurement indicates antiferromagnetic interactions between Ce³⁺ cations.