Evidence for the First Misfit Layer Oxide Tl_0.41(Sr_0.9O)_1.12CoO₂

Abstract

A misfit layer oxide Tl0.41(Sr0.9O)1.12CoO2 has been synthesized, and its structural model established by ED and HREM. The cell parameters of the two subsystems have been refined from XRPD data. The subsystem S1 (a = 4.9498(5) Å, b 1 = 5.0222(6) Å, c = 11.656(1) Å, β = 97.755(7)°) characterizes the strontium-deficient rock-salt layers [(Sr0.9□0.1)O]∞, whereas the subsystem S2 (a = 4.9498(5) Å, b 2 = 2.807(2) Å, c = 11.656(1) Å, β = 97.755(7)°) corresponds to the octahedral [CoO2]∞ layers that exhibit the CdI2 structure. The thallium atoms are located between the two kinds of layers, with a distorded tetrahedral coordination, ensuring the cohesion of the structure.

Structure and microstructure of the high pressure synthesised misfit layer compound [Sr2O2][CrO2]1.85

“…Apart from this oxide, in other cobaltites, despite being shorter when compared to sulphides, the shortest intrasubsystem distance alternates from shorter to longer than the intrasubsystem interaction along t [29,30,38,39]. However, in this Sr-Cr misfit oxide, both shortest distances become shorter for the same t Regarding the modulation in the distances of the RS-type layer of the Sr-Cr misfit, the largest difference between the maxima and minimum Sr-O1 distance for the same bond is that observed for O1 1 30,40]. These hydroxides present very short Ca-OH distances, with very large in-plane deformations in the CaOH layers, which are attributed to the HP employed in the synthesis.…”

“…In the last 10 years, a big effort has taken place in the synthesis and characterisation of a type of incommensurate oxide structures named as misfit layer compounds [1][2][3]. Besides their intrinsic importance as structurally unusual solids they have the added interest that many of them, in particular some mixed cobalt oxides, have been shown to have interesting thermoelectric properties, apparently related to their complex structures [4,5].…”

A five-dimensional structural investigation of the misfit layer compound [Bi0.87SrO2]2[CoO2]1.82

“…A structural model has been proposed where three-atom thick [(Sr 1Àx Bi x )O] I layers with a distorted RSS are intercalated between single pseudohexagonal (HL) [CoO 2 ] I layers of edge-sharing CdI 2 -type octahedra. These Bi-based composite structures are closely related to the mis®t layered chalcogenides (MX) 1x (TX 2 ) m , a class of materials which are important for their crystal chemistry as well as their physical properties (Rouxel, 1996;Wiegers & Meerschault, 1992), and to the recently reported mis®t layered cobaltite Tl [(AO)] 1x [CoO 2 ], with A = Ca and Sr (Boullay et al, 1996(Boullay et al, , 1998.…”

Fabrication and thermoelectric characteristics of [(Bi,Pb)2Ba2O4±w]0.5CoO2 bulks with highly aligned grain structure

“…Noticeable is that the two layers are incoherently or "misfittingly" coupled with each other along the b axis such that the q value is often fractional. 7,8 This "nanocomposite" structure consisting of highly conductive CoO 2 layers and insulating RS layers is essential for the superb TE characteristics of misfit-layered cobalt oxides. In fact, single crystalline samples of some misfit-layered materials have been reported to possess high values of figure of merit, e.g., ZT Ϸ 1.0, at temperatures above 500°C.…”