SnI ⋅(S ) : A Novel Adduct-Type Infrared Second-Order Nonlinear Optical Crystal.

A simple adduct from tin tetraiodide SnI and octasulfur S , SnI ⋅(S ) (1), is obtained employing a facile reaction. The combination of Sn ions with d electron configuration, acentric SnI tetrahedra, and lone-pair effects of S , makes 1 a phase-matchable infrared NLO crystal with a moderate second-harmonic generation (SHG) response and a very high laser-induced damage threshold (LIDT), which is well confirmed by the DFT calculations.