Etude structurale des oxysulfures de chrome(III) et de terres rares. II. Structure de l'oxysulfure CeCrOS2

Abstract

CeCrOS 2 is monoclinic, space group B2/m, with unit-cell constants a = 11.518 (6), b = 7.951 (4), c = 3.703 (4) A, y = 90.07 (6) °, z = 4, O m : 5.4 (1), D x = 5-33 Mg m -3. The crystal structure has been determined from four-circle diffractometer data using Patterson and Fourier syntheses and refined by the least-squares method to a final R value of 0.025 for 778 observed structure factors. The Ce atom is nine-coordinated in tricapped trigonal prisms containing three O and six S atoms; the Cr atom is six-coordinated in two types of octahedra: [CrS 6] and [CRO254]. The structure shows a three-dimensional arrangement and can be regarded as being built up from layers of [CeO3S 6] polyhedra alternating with layers of [CrOSs I octahedra.

Synthesis of Ce2O2S and Gd2(1–y)Ce2yO2S Nanoparticles and Reactivity from in Situ X-ray Absorption Spectroscopy and X-ray Photoelectron Spectroscopy

“…These synthesis techniques employ various sulfur sources (elemental sulfur, H 2 S, or CS 2 ) as sulfidation agents. Some of them also involve a transition metal, producing bimetallic compounds, such as Ln 2 Ti 2 S 2 O 5 and LnCrOS 2 (Ln = La-Lu) [3][4][5] , but also LaInOS 2 and La 5 In 3 S 9 O 3 . 6 Ln 2 O 2 S nanoparticles have been extensively studied and characterized for their promising magnetic [7][8][9] , photocatalytic 8 and luminescent properties 10,11 .…”

Anion Ordering in Bichalcogenides

“…As a result, the crystal structure of CeCrS2O consists of layers ( Figure 6, right) built from two different octahedra that are edge-and vertex-sharing and are separated by Ce 3+ ions. The structural difference between the two chemically similar systems can be described as a coordination disproportionation: LaCrS2O contains only [CrS3/3S2/2O1/1] 3 entities [48] and CeCrS2O contains equal amount of [CrS4/2S2/3] 7/3 and [CrS4/3O2/1] 11/3 octahedra in an ordered fashion [54] (Figure 6). As it is clearly not a charge ordering phenomenon, this might be related to coordination order entropy that is rarely taken into consideration.…”

Bad‐Metal‐Layered Sulfide Oxide CsV2S2O

“…There are only few such compounds, e.g. CeCrS 2 O 4. However, the title compound is different because of the formally mixed valence of TM .…”

“…Layered transition‐metal ( TM ) systems are in focus of solid‐state research since the discovery of the high‐temperature superconductivity in the copper oxides 1. Partially introducing a heavier chalcogenide in the oxygen anionic lattice while simultaneously keeping the quasi‐octahedral TM coordination led to the discovery of several new layered structures: La 2 TM 2 Se 2 O 3 ( TM = Fe,2 Co3) with layers of ∞ 2 [ TM Se 4/4 O 2/4 ], CeCrS 2 O with a 2D net of ∞ 2 [CrS 4/2 S 2/3 ,CrS 4/3 O 2 ],4 and Sr 2 TM Cu 2 S 2 O 2 ( TM = Co, Ni, Cu)5 with layers of ∞ 2 [ TM S 2/1 O 4/2 ]. Further, Sm 2 Ti 2 S 2 O 5 contains double layers of ∞ 2 [TiO 5/2 ],6 whereas layers of ∞ 2 [VS 6/3 ] are found in Sr 6 V 9 S 22 O 2 7,8.…”