Hg₃(SeO₃)₂(SO₄): A UV Nonlinear Optical Mercury Selenite Sulfate Constructed by Neat [Hg₆O₈(SeO₃)₄]_∞ Layers and SO₄ Tetrahedra

Abstract

A novel mercury selenite sulfate named Hg3(SeO3)2(SO4) has been successfully synthesized under a mild hydrothermal method. Hg3(SeO3)2(SO4) crystallizes in a monoclinic space group P21 and features a unique three-dimensional (3D) frame structure formed by [Hg6O8(SeO3)4]∞ layers and SO4 tetrahedra, which enables it to exhibit a comprehensive performance of a moderate second-harmonic generation (SHG) response of approximately 1.3 times that of baseline KH2PO4 (KDP), a moderate birefringence (0.118@546 nm), and a wide band gap (4.70 eV), which indicates that it has potential for application as an ultraviolet (UV) nonlinear optical material. Detailed theoretical calculations show that the Hg2+-based polyhedra with large polarizability and deformability and the SeO3 groups with stereochemically active lone pair (SCALP) electrons are the main contributors to moderate optical properties.

A UV non-hydrogen pure selenite nonlinear optical material for achieving balanced properties through framework-optimized structural transformation

“…The birefringence at 546 nm and 1064 nm is 0.138 and 0.128, respectively, close to the measured value (0.153@546 nm). These values are comparable to those of Hg 2 (SeO 3 )(SO 4 ) (0.133@ 532 nm and 0.126@1064 nm), 58 Hg 3 (SeO 3 ) 2 (SO 4 ) (0.118@546 nm) 59 and CaYF(SeO 3 ) 2 (0.138@532 nm and 0.127@1064 nm). 31 This birefringence is large enough to satisfy the phase-matching condition (Fig.…”

AX·(H2SeO3)n (A = K, Cs; X = Cl, Br; n = 1, 2): A Series of Ionic Cocrystals as Promising UV Birefringent Materials with Large Birefringence and Wide Band Gap

“…28,29 with second-order Jahn− Teller (SOJT) distortions to enhance the optical properties. polyhedra of SOJT distortive cations have been reported to exhibit large birefringence and SHG response, such as Hg 2 (SeO 3 )(SO 4 ) (0.133 at 532 nm, 3.58 eV), 30 Hg 3 (SeO 3 ) 2 (SO 4 ) (0.105 at 546 nm, 4.7 eV), 31 NaNbO-(SeO 3 ) 2 (0.287 at 1064 nm, 3.65 eV), 32 Ba(MoO 2 F) 2 (SeO 3 ) 2 (0.18 at 1064 nm, 3.3 eV), 33 Bi 2 [B 2 (SeO 3 ) 6 ] (0.09 at 1064 nm, 3.83 eV), 34 Cs(TiOF) 3 (SeO 3 ) 2 (0.279 at 1064 nm, 3.5 eV), 35 Sc(HSeO 3 ) 3 (0.105 at 1064 nm, 5 × KDP, 5.28 eV), 36 PbBi(SeO 3 ) 2 F (0.103 at 1064 nm, 10.5 × KDP, 3.75 eV), 37 Pb 2 Bi(SeO 3 ) 2 Cl 3 (0.186 at 1064 nm, 13.5 × KDP, 3.45 eV), and RbGa 3 F 6 (SeO 3 ) 2 (0.101 at 546 nm, 5.6 × KDP, 3.57 eV). 38 So the above strategy, namely the introduction of SOJT distortive cations into selenite, could indeed be of great help in improving optical anisotropy, but it will cause the decrease in the optical band gap, which is unfavorable for the laser-induced damage threshold (LIDT) and the potential application in the UV region.…”

Two Short-Wave UV Antimony(III) Sulfates Exhibiting Large Birefringence

“…Several strategies have been shown to be effective in improving the total optical anisotropy: (1) the introduction of halogens into tetrahedral groups to break T d symmetry; 23,24 (2) the introduction of d 10 transition metal cations to increase the birefringence; 25,26 and (3) the introduction of cations with stereochemically active lone-pair (SCALP) electrons, for example, Te 4+ and Bi 3+ , to enhance total optical anisotropy. 27,28 Currently, many compounds with large birefringence have been discovered based on Bi 3+ and Te 4+ , such as Bi(IO 3 )(SO 4 ) (0.087@1064 nm), 29 KBiSO 4 Cl 2 (0.098@1064 nm), 30 and Ba 2 TeP 2 O 9 (0.126@1064 nm).…”