New Bismuth Selenium Oxides: Syntheses, Structures, and Characterizations of Centrosymmetric Bi₂(SeO₃)₂(SeO₄) and Bi₂(TeO₃)₂(SeO₄) and Noncentrosymmetric Bi(SeO₃)(HSeO₃)

Abstract

Three new mixed metal selenium oxides materials, Bi2(SeO3)2(SeO4), Bi2(TeO3)2(SeO4), and Bi(SeO3)(HSeO3), have been synthesized by hydrothermal and solid-state reactions using Bi(NO3)3·5H2O, SeO2 (or TeO2), H2SeO4, and Bi2O3 as reagents. The reported materials have been structurally characterized by single crystal X-ray diffraction. While Bi2(SeO3)2(SeO4) and Bi2(TeO3)2(SeO4) are crystallographically centrosymmetric (CS), Bi(SeO3)(HSeO3) crystallizes in a noncentrosymmetric (NCS) space group. The isostructural Bi2(SeO3)2(SeO4) and Bi2(TeO3)2(SeO4) exhibit three-dimensional framework structures that are composed of BiO6, Se(4+)O3 (or Te(4+)O3), and Se(6+)O4 polyhedra. However, Bi(SeO3)(HSeO3) exhibits corrugated layers that are composed of BiO5, Se(4+)O3, and Se(4+)O2(OH) polyhedra. All three materials contain local asymmetric coordination environments attributable to the lone pairs on the Bi(3+), Se(4+), and/or Te(4+) cations. Powder second-harmonic generation (SHG) measurements on NCS Bi(SeO3)(HSeO3) using 1064 nm radiation indicate that the material has a SHG efficiency of approximately 20 times that of α-SiO2 and is not phase-matchable (type 1). The origin and magnitude of the SHG efficiency of Bi(SeO3)(HSeO3) is explained by determining the net direction of the polarizations arising from individual asymmetric polyhedra. Infrared spectroscopy, thermal analysis, elemental analysis, and dipole moment calculations for the reported materials are also presented.

Ag4Hg(SeO3)2(SeO4): a novel SHG material created in mixed valent selenium oxides by in situ synthesis

“…Furthermore, [53]. In most of the selenite-selenate compounds, the SeO 3 and SeO 4 groups bridge the cationic polyhedra to an expanded structure together [23][24][25][26][27][28][29][30][31][32].…”

“…They prefer NCS tetrahedral geometry when coordinated with oxygen atoms. So, mixed-valence selenite-selenates are such compounds in which polar triangular pyramidal Se(IV)O 3 and NCS tetrahedral Se(VI)O 4 exist simultaneously [23][24][25][26][27][28][29][30][31][32]. Based on the literature research, we found the reported inorganic selenite-selenate compounds are still rare.…”

“…Based on the literature research, we found the reported inorganic selenite-selenate compounds are still rare. And only Au 2 (SeO 3 ) 2 (SeO 4 ) [26] (Cmc2 1 , 0.43 × KDP) was studied by SHG measurements although six mixed-valent selenium oxides were crystalized in NCS space group [23][24][25][26][27][28].…”

“…Most of the reported selenite-selenate compounds were prepared by in situ syntheses [23][24][25][26][27][28][29][30][31][32]. The mixed-valent selenium atoms were achieved by partial reduction of the hexavalent selenic acid or oxidation of the tetravalent selenium dioxide.…”

Incorporation of Sulfate or Selenate Groups into Oxotellurates(IV): I. Calcium, Cadmium, and Strontium Compounds

“…So far, only a few metal oxotellurate(IV) phases with additional X O 4 groups have been reported, mostly prepared under hydrothermal conditions. This includes the sulfates Al 2 (OH) 2 (SO 4 )(TeO 3 ), Fe 2 (TeO 3 ) 2 (SO 4 )(H 2 O) 3 , Cu 7 (OH) 6 (TeO 3 ) 2 (SO 4 ) 2 , Cu 7 TeO 4 (SO 4 ) 5 KCl, the series RE 2 M (TeO 3 ) 2 (SO 4 ) 2 ( RE = rare earth metal; M = Cu, Co, Zn),, Pu(TeO 3 )(SO 4 ), Th(TeO 3 )(SO 4 ), Ce 2 (Te 2 O 5 )(SO 4 ) 2 , M 2 (TeO 3 )(SO 4 )H 2 O ( M = Co, Mn), and BiCu 2 (TeO 3 )(SO 4 )‐(OH) 3 , and to a much lesser extend the selenates Sc 2 (TeO 3 )‐(SeO 3 )(SeO 4 ) (also comprising an oxoselenate(IV) group), Bi 2 (TeO 3 ) 2 (SeO 4 ) and the already noted mercury compounds Hg 3 (SeO 4 )(TeO 3 ) 2 and Hg 3 (SeO 4 )(Te 4 O 10 ) …”