Synthesis, Crystal and Electronic Structures, and Nonlinear Optical Properties of Y 4 Si 3 S 12

A new acentric sulfide Y 4 Si 3 S 12 was grown by a high temperature vapor transport reaction. The crystal structure of Y 4 Si 3 S 12 was determined by single crystal X‐ray diffraction. Y 4 Si 3 S 12 is isostructural to La 4 Ge 3 S 12 . The three dimensional structure of Y 4 Si 3 S 12 is constructed by [Y1S 7 ] augmented triangular prisms, [Y2S 6 ] triangular prisms and [SiS 4 ] tetrahedra through sharing vertices and edges. Y 4 Si 3 S 12 is revealed as an indirect bandgap semiconductor with a calculated bandgap of 2.1 eV, which is close to 2.5(1) eV experimentally measured by UV‐Vis. The Y−S interactions and Si−S interactions are predicated to be strong ionic bonds and covalent bonds, respectively, by electron localization function coupled with crystal orbital Hamilton population calculations. Y 4 Si 3 S 12 is verified by DFT calculations to have moderate birefringence, with incident 1900 nm laser, Δn=0.09. DFT calculations also predicted that Y 4 Si 3 S 12 possesses moderate second harmonic generation response with χ 111 =15.03 pm/V. The nonlinear optical properties of Y 4 Si 3 S 12 are mainly contributed by Y−S interactions revealed by DFT calculations.