Kationenverteilung und Überstrukturordnung in ternären und quaternären Sulfidspinellen M^IIMS₄ – Einkristallstrukturuntersuchungen

Abstract

Die Kristallstrukturen der Spinelle MIn2S4 (M  Mn, Co, Ni), MCr2–2xIn2xS4 (M  Mn, Ni) and Cd0,52Co0,48Cr2S4 wurden an durch Gasphasentransport erhaltenen Einkristallen neu bestimmt. Die Indiumsulfide besitzen eine partiell inverse Verteilung der Metallionen auf die Tetraeder(8a)‐ und Oktaederplätze(16d) der Struktur. Die Inversionsgrade γ betragen 0,34 (MnIn2S4, a = 1072,0(1) pm, Lageparameter u = 0,25726(2)), 0,84 (CoIn2S4 a = 1058,1(l)pm, u = 0,25921(5)) und 0,93 (NiIn2S4, a = 1050,5(1), u = 0,26040(3)). Die Inversionsgrade und Lageparameter der Chromindiumsulfidspinell‐Mischkristalle zeigen eine annähernd lineare Abhängigkeit von der Zusammensetzung x. ψ‐scans der in der Raumgruppe Fd3m symmetrieverbotenen Reflexe ergaben keinen eindeutigen Nachweis auf Mehrfachreflexion. Eine Verfeinerung der Strukturen des MnIn2S4 und des Cd0,52Co0,48Cr2S4 in der Raumgruppe F43m ergab eine partielle Überstrukturordnung des Mangans und Indiums bzw. Cadmiums und Cobalts auf den Tetraederplätzen der Struktur, 4a‐Lage: Mn0,83In0,17, Cd0,41Co0,59 4c: Mn0,49Ino,51, Cd0,52Co0,38.

Structural and Local Environment Modifications in a Chemically Lithiated Iron Thiospinel

“…This result is in good agreement with previous studies (11). First-row transition metal indium sulfides have a partially inverse distribution with the metal ions in both tetrahedral and octahedral sites (8,12). Thus, the doublet with the larger quadrupole splitting can be unambiguously ascribed to Fe> ions in octahedral 16d sites, while the second doublet in the central part of the spectrum is due to Fe> ions in tetrahedral 8a sites.…”

Magnetic properties of the Mn1−xFexIn2S4 spinel compounds

“…From the fitting we obtained the paramagnetic Curie temperature θ = −29 K for sample with x = 0.3 and θ = −76 K for sample with x = 0.8. The negative sign indicates that the predominant magnetic interactions are antiferromagnetic [7].…”

Structural characterization and magnetic properties of the spinel compound CoIn0.5Cr1.5S4

“…The peak positions of the interest phase were indexed using the program Dicvol04 [12], which gave a unique solution in a cubic cell. The Rietveld refinement [13] was performed using the Fullprof [14] [9] were included as a second phase in the refinement. The refined parameters included zero shift, scale factors, asymmetry parameter, coefficients for the polynomial describing the background; U, V ,W, and mixing parameters of the pseudo-Voigt peak-shape function, unit cell parameters, positional parameters, overall isotropic temperature factors for each phases, and the occupancy factors for the Cr and In cations.…”

“…Thus, CoCr 2 S 4 has been described as a ferrimagnetic semiconductor with a critical temperature of 223 K [5], which is the highest Curie temperature among the mentioned ternary chromium sulfides compounds [6,7]. For the other hand, the CoIn (2-2X) Cr (2X) S 4 semiconducting system is very attractive from the magnetic and crystallographic viewpoint, because the phase with x = 1 (CoCr 2 S 4 ) crystallizes with a normal spinel structure [1] while the phase with x = 0 (CoIn 2 S 4 ) crystallizes with a inverse spinel structure [8,9]. From the magnetic point of view should be interesting to study the influence of the In 3+ admixtures on the cation distribution and magnetic ordering in this spinel.…”