Room-temperature structure of La2O2S2

Oxysulfide Ba5(VO2S2)2(S2)2 Combining Disulfide Channels and Mixed-Anion Tetrahedra and Its Third-Harmonic-Generation Properties

“…Considering other low-dimensional systems, disulfide pairs are found in the layered phases [A 2 O 2 ]­(S 2 ) (A = La, Pr, Nd), which are constituted by the alternative stack of fluorite-type [A 2 O 2 ] 2+ layers and disulfide (S 2 ) 2– layers arranged in a planar sheet. In particular, the La 2 O 2 S 2 phase (Figure ) crystallizes in the space group Cmce with a band gap of ∼2.55 eV and exhibits photoluminescent properties upon doping…”

“…In particular, the La2O2S2 phase (Fig. 3) crystallizes in the Cmce space group34 with a band gap 2.55 eV and exhibits photoluminescent properties upon doping35 .…”

Layered CeSO and LiCeSO Oxide Chalcogenides Obtained via Topotactic Oxidative and Reductive Transformations

“…Despite the removal of almost all the Ag + from the tetrahedral sites in the sulfide layers, there is no evidence for the formation of S–S bonds following this oxidative deintercalation. This contrasts with the case for compounds with trivalent lanthanides in which compounds of formula LnSO contain [S 2 ] 2– ions . The preliminary analyses of diffraction patterns of CeSO samples measured using high-resolution synchrotron X-ray diffraction using peak shapes with only Gaussian and Lorentzian terms to account for particle size and strain broadening (as used in the refinement of the LiCeSO model) were inadequate (Figure S4).…”

“…This contrasts with the case for compounds with trivalent lanthanides in which compounds of formula LnSO contain [S 2 ] 2− ions. 56 The preliminary analyses of diffraction patterns of CeSO samples measured using high-resolution synchrotron X-ray diffraction using peak shapes with only Gaussian and Lorentzian terms to account for particle size and strain broadening (as used in the refinement of the LiCeSO model) were inadequate (Figure S4). Such a refinement gave a numerical goodness of fit parameter χ 2 of 3.03 but generally accounted poorly for the shapes of the peaks: the hk0 reflections were relatively narrow compared with the widths of hkl reflections.…”

“…These include CeS 1.9 and two polymorphs of CeS 2 in which S−S distances in the [S 2 ] 2− anions are similar, within the uncertainties, to those found for the analogous compounds with the less oxidizable light lanthanides at 2.154(8) Å for α-CeS 2 and 2.115(3) for β-CeS 2 , 67 distances characteristic of [S 2 ] 2− anions (cf., 2.103(3) Å in the [S 2 ] 2− ions of LaSO). 56 Thus, Ce 4+ readily oxidizes sulfide, and this may reflect the difficulty in completely deintercalating all the Ag from CeAg 0.8 SO to obtain pure CeSO. In contrast, CeSO, with no S−S contacts shorter than 3.23 Å, resembles other systems with only monosulfide ions, e.g., ZrS 2 with no S−S contacts shorter than 3.59 Å (a Zr 4+ compound with six-coordinate Zr in the CdCl 2 structure type), 68 and ThS 2 with no S−S contacts shorter than 3.19 Å (a Th 4+ compound with nine-coordinate Th in the PbCl 2 structure type).…”