Systematic and design of noncentrosymmetric sulfides and selenides for nonlinear optics

The sets of 412 noncentrosymmetric (NCS) binary and >130 ternary sulfides and 160 binary selenides have been compilled and classified. The elliptical regions on the plane of the shortest chemical bond lengths between cations and sulphur have been defined. The NCS crystals are located only into these regions. Relationship between nonlinear optical susceptibility χ(2) and chemical bonding in sulfides has been considered. The intervals of the shortest cation–anion bond lengths promising for high rank χ(2) have been estimated for the compounds.