Related Experiment Video
Updated: Oct 7, 2025
Synthesis of a Thiol Building Block for the Crystallization of a Semiconducting Gyroidal Metal-sulfur Framework
Published on: April 9, 2018
Two Nonlinear Optical Thiophosphates Cu5Hg0.5P2S8 and AgHg3PS6 Activated by Their Tetrahedra-Stacking Architecture
Yang Wang1,2,3, Yuqiang Fang2, Yunzhen Cao1
1Key Laboratory of Inorganic Coating Materials CAS, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800, China.
Abstract:
Infrared (IR) lasers are very critical in military and civil affairs, but it is also challenging and difficult to develop new infrared nonlinear optical (NLO) crystals. Herein, two new mixed-metal thiophosphates, Cu5Hg0.5P2S8 and AgHg3PS6 were discovered with the noncentrosymmetric (NCS) space group Pmn21 (No. 31) and Cc (No. 9). Cu5Hg0.5P2S8 displays a three-dimensional (3D) defective diamond-like structure stacked by ∞2[Cu2.5Hg0.25PS8]8- layers. AgHg3PS6 is characterized by a 3D framework consisting of distorted tetrahedrons. Moreover, the optical spectra show the band gaps of Cu5Hg0.5P2S8 and AgHg3PS6 are 2.12 and 1.85 eV, respectively, with a broad transparent range of 0.7-16.0 μm. In these two compounds, the dipole moments of nonlinear active units are strengthened due to the high-valence element P and the Hg-S bonds with large susceptibility. Therefore, AgHg3PS6 exhibits a moderate second harmonic generation (SHG) response that is half that of AgGaS2 (AGS) at 30-45 μm, while Cu5Hg0.5P2S8 performs a phase-matching (PM) behavior with a good SHG signal of 0.8 × AGS at 150-200 μm. The origin of NLO performance and electronic structures were revealed by the calculated dipole moments of distorted tetrahedra and theoretical calculations on the basis of density functional theory.
Related Concept Videos
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
02:37Metallic Solids
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability....
02:42Valence Bond Theory
03:35Hybridization of Atomic Orbitals II
03:02Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
02:58Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...