Birefringent materials are very important in the laser industry. By combining the hexathiodiphosphate(IV) [P 2 S 6 ] 4- unit and the highly polarizable Hg 2+ , a mercury hexathiodiphosphate(IV) Hg 2 P 2 S 6 was designed and synthesized by using solid-state synthesis. Hg 2 P 2 S 6 crystallizes in P 1 ¯ space group. It has a layered structure as in many hexathiodiphosphates(IV) such as ZnPS 3 , CdPS 3 . Its crystal structure, electronic structure and optical properties are investigated by experimental methods and first-principle calculations. Hg 2 P 2 S 6 has a very large birefringence of 0.50 at 1064 nm and 0.48 at 2050 nm. Theoretical studies show the large birefringence comes from the synergistic effect of [P 2 S 6 ] 4- and [HgS 4 ] 6- groups with strong polarizability anisotropy.
The ternary thiophosphate PbPS3 was synthesized by a high-temperature solid-state reaction using PbS, P and S. Single-crystal X-ray diffraction analysis reveals that the compound crystallizes in the P21/c space group. It features a three-dimensional structure, which consists of [PbS8] hendecahedra and isolated ethane-like [P2S6]4− units. PbPS3 can be easily obtained by different methods and shows high air stability, which is beneficial to its chemical synthesis and large-sized crystal growth. The crystal structure, optical properties and electronic structure of PbPS3 have been researched by experimental methods and first-principles calculations. The results show that PbPS3 has a moderate bandgap (Eg. exp. = 2.60 eV) and birefringence (Δncal. = 0.094@1064 nm), as well as a wide transparent range. Furthermore, to better understand the origin of the birefringence, structure comparisons and theoretical calculations were carried out. With a relatively high physicochemical stability and easy synthesis, PbPS3 can be expected to be a prospective birefringent material.
危险品化学品经营许可证（带存储）