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[Ge 2 S 5 (S 2 )] 4− , A NLO‐Active Unit Leading to an Asymmetric Structure Discovered in Li 2 Cs 4 Ge 2 S 5 (S 2 )Cl 2 : An Experimental and Theoretical study
Author(s) -
Li Guangmao,
Wu Kui,
Huang Yi,
Yang Zhihua,
Pan Shilie
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201901012
Subject(s) - unit (ring theory) , physics , atomic physics , crystallography , chemistry , mathematics , mathematics education
Metal‐centered MS 4 tetrahedra are fundamentally important building blocks for the structural construction of infrared (IR) nonlinear optical (NLO) mateirals, because they have a large effect on properties like second‐harmonic generation, birefringence, band gap, etc. Therefore, rational design and selection of these tetrahedra could effectively help synthesize new materials and give satisfactory properties. In this work, we reported a new NLO‐active [Ge 2 S 5 (S 2 )] 4− unit composed of two corner‐shared GeS 4 tetrahedra with a nonpolar covalent S−S bond, discovered in a new compound of Li 2 Cs 4 Ge 2 S 5 (S 2 )Cl 2 . To the best of our knowledge, this [Ge 2 S 5 (S 2 )] 4− unit has never been discovered. [Ge 2 S 5 (S 2 )] 4− units have intrinsic asymmetric features and lead to the whole structure being noncentrosymmetric (NCS). Further, real‐space atom‐cutting methods reveal that they make almost all the contribution to the second‐harmonic generation response (SHG) for Li 2 Cs 4 Ge 2 S 5 (S 2 )Cl 2 . All of the above indicate that the [Ge 2 S 5 (S 2 )] 4− unit is a new functional unit and a good choice for designing new IR NLO materials.