Reinvestigation of Hg₂GeSe₄based on single-crystal data

Abstract

Dimercury(II) germanium(IV) tetraselenide, Hg2GeSe4, adopts a cation‐deficient diamond‐like structure. It crystallizes in space group I of the tetragonal system. The structure consists of tetrahedral [HgSe4] and [GeSe4] groups. These groups are interconnected by sharing common corners. The previous structure report on Hg2GeSe4 based on powder diffraction data [Parasyuk et al., (2003). J. Alloys Compd, 351, 135–144] is comparable with our results except for the absolute configuration determination. In the asymmetric unit, the site symmetries of the Hg and Ge atoms are .

Nonbonding Electrons Driven Strong SHG Effect in Hg2GeSe4: Experimental and Theoretical Investigations

“…27 In this Communication, we propose that special attention should be paid to the defect DL structures, which possess perfect alignment of functional units and nonbonding electron states owing to the deficiency of unoccupied cation sites. We systematically investigated the optical properties of ternary Hg-containing defect DL selenide Hg 2 GeSe 4 28 for the first time. Experiment results show that Hg 2 GeSe 4 exhibits a strong NLO effect about 2.1 times that of the benchmark AgGaSe 2 (d 36 = 33 pm/V) in the particle size range 150−200 μm and is found to be phase-matchable.…”

The Tl2Se–HgSe–GeSe2 system and the crystal structure of Tl2HgGeSe4

“…Tl 2 Ge 2 Se 5 also has a monoclinic structure (space group C2/c), with the lattice parameters а = 0.8481(2) nm, b = 0.8411(2) nm, с = 1.5800(5) nm, β = 107.10(3)º [25]. An investigation of the HgSe-GeSe 2 system [26] showed the existence of the ternary compound Hg 2 GeSe 4 , which forms in a peritectic reaction at 893 K and has a polymorphous transition at 830 K. Its low-temperature modification has a tetragonal cadmium thiogallate-type structure (space group І-4) with the lattice parameters а = 0.5672 nm, с = 1.1322 nm [26] (or а = 0.56786 nm, с = 1.12579 nm [27]; а = 0.56741 nm, с = 1.1249 nm [28]).…”