KHg₄Ga₃S₉: A Hg-Based Sulfide with Nonlinear-Optical Activity in the A–M^II–M^III–Q (A = Alkali Metal; M^II = d¹⁰ Metal; M^III = Ga, In; Q = S, Se) System

Abstract

The search for new high-performance infrared (IR) nonlinear-optical (NLO) materials is a hot topic in the fields of laser chemistry and inorganic solid-state chemistry. Here, a new Hg-based sulfide KHg4Ga3S9 in the family of A–MII–MIII–Q (A = alkali metal; MII = d10 metal; MIII = Ga, In; Q = S, Se) was synthesized. It crystallizes in the orthogonal system of the C2221 structure, which is rare for IR NLO chalcogenides. Its anionic framework {[Hg4Ga3S9]−}∞ is constructed by two types of interconnected helical chains, viz., the inner layer ({[Hg6Ga2S29/3]4/3–}∞) and the outer layer ({[Hg2Ga4S25/3]2/3–}∞). It exhibits a moderate NLO response and a high laser-induced damage threshold. Theoretical calculations indicate that the HgS4 unit accounts for its much larger NLO response compared to RbCd4Ga3S9. The influence of alkali metals and d10 metals on the initial phase-matching wavelength is also discussed. This work provides inspiration for improving the properties of NLO materials’ properties.

Hg3Se(SeO3)(SO4): A Mixed-Valent Selenium Compound with Mid-Infrared Transmittance Obtained by In Situ Reaction

“…The UV cutoff edge is ∼282 nm, corresponding to a band gap of 3.5 eV (Figure S6). It is comparable with the previously reported sulfate–selenite mercury of Hg 2 (SeO 3 )­(SO 4 ) (3.58 eV), which far exceeds the previously reported Hg-based chalcogenide compounds such as Ba 2 HgTe 5 (1.28 eV), AgHgPS 4 (2.63 eV), (Na 3 Rb)­Hg 2 Ge 2 S 8 (2.76 eV), KHg 4 Ga 3 S 9 (3.0 eV), BaHgGeS 4 (3.04 eV), and Zn 2 HgP 2 S 8 (3.37 eV) . Compared to the bandgap of 2.63 eV for (Hg 3 Se 2 )­(Se 2 O 5 ), the band gap of Hg 3 Se­(SeO 3 )­(SO 4 ) is significantly improved, due to the effect of SO 4 .…”

Sr2HgGe2OS6: A Hg-Based Oxychalcogenide Infrared Nonlinear Optical Material Exhibiting Favorable Balance between a Large Band Gap and Strong Second Harmonic Generation Response

“…The Ge–S bond lengths of 2.140(4)–2.211(1) Å are equivalent to the 2.205(3)–2.210(4) Å range reported in Sr 3 S­[GeOS 3 ] . Each Hg atom is coordinated with four S1 atoms to form the typical [HgS 4 ] tetrahedron with four identical Hg–S bond lengths of 2.498(2) Å (Figures b and S1b), which is also comparable to the result of 2.405(4)–2.920(3) Å reported in KHg 4 Ga 3 S 9 . In the structure of Sr 2 HgGe 2 OS 6 , two neighboring [GeOS 3 ] units form [Ge 2 OS 6 ] dimers by sharing O atoms, then the [Ge 2 OS 6 ] dimers are connected to the [HgS 4 ] tetrahedra by sharing S1 atoms, as shown in Figure a.…”

A2Hgx(SeO3)y (A = K, Rb, Cs): Three Alkali Metal Mercury Selenites Featuring Unique 1D [HgOm(SeO3)n]∞ Chains

“…This characteristic effectively increases the second harmonic generates response and birefringence, as confirmed by LiHgPO 4 , Hg 3 O 2 SO 4 , CsHgNO 3 Cl 2 , and so on. Moreover, due to the absence of d–d and f–f transitions, alkali metal ions can efficiently widen the band gap …”