title: Phase Transition and Second Harmonic Generation in Thiophosphates Ag2Cd(P2S6) and AgCd3(PS4)S2Containing Two Second-Order Jahn-Teller Distorted Cations.
abstract: Two new phases in the Ag-Cd-P-S system containing two second-order Jahn-Teller (SOJT) distorted d10cations (Cd2+and Ag+), namely, Ag2Cd(P2S6) (1) and AgCd3(PS4)S2(2), are obtained via medium-temperature solid-state synthesis. Compound 1 exhibits a two-dimensional layered structure and undergoes a first-order structural phase transition at approximately 280 °C. This outcome can be ascribed to the significant mismatch in the expansion coefficients between Cd-S (Ag-S) and P-P (P-S) bonds evaluated through bond valence theory. The three-dimensional non-centrosymmetric (NCS) framework of 2 is constructed by two types of tetrahedral layers consisting of corner-shared CdS4, AgS4, and PS4tetrahedra. Compound 2 exhibits second harmonic generation (SHG) intensity of 0.45 times that of commercial AgGaS2(AGS) at a laser irradiation of 1.85 μm and an optical band gap of 2.56 eV, and no intrinsic vibrational absorption of chemical bonds is observed in the range of 2.5-18.2 μm. Both phase transition in 1 and SHG properties in 2 are closely related to the SOJT distorted d10cations and diverse phosphorus-sulfur polyanions (PaSb)n-, which together can easily result in NCS distorted structures and interesting properties.
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, People' s Republic of China.
authors.forename: Yu-Hang
authors.initials: YH
authors.lastname: Fan
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, People' s Republic of China.
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, People' s Republic of China.
authors.forename: Bin-Wen
authors.initials: BW
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, People' s Republic of China.
authors.forename: Shu-Fang
authors.initials: SF
authors.lastname: Li
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, People' s Republic of China.
authors.forename: Wei-Huan
authors.initials: WH
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, People' s Republic of China.
authors.forename: Hui-Yi
authors.initials: HY
authors.lastname: Zeng
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, People' s Republic of China.
authors.forename: Guo-Cong
authors.identifier: http://orcid.org/0000-0002-7450-9702
authors.initials: GC
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, People' s Republic of China.
authors.forename: Jin-Shun
authors.initials: JS
authors.lastname: Huang