Modulated Structure of the Composite Crystal [2CaOH]_kCoO₂(k=0.576)

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

“…It can be seen that it is composed of the alternate stacking along c of 1 layer of CrO 2 and 2 layers of SrO, with consecutive CrO 2 layers related by a (001) mirror; this is responsible of the resulting orthorhombic symmetry. This type of orthorhombic stacking has been observed in sulphides [12] as well as in cobalt oxides and hydroxides [29,30].…”

“…This strong M(u ¼ 1)-O2(u ¼ 2) bond is also found in the Sr-Bi cobaltite, where it is enhanced by the weak BiO-BiO intrasubsystem interaction within the four atoms thick rock salt-type layer [3]. 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].…”

“…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.…”

Structure of the Monoclinic-Form Misfit-Layer Compound, (Ca0.85OH)2αCoO2 (α ≈ 0.57822)

“…In the present case of (Ca 0.85 OH) 1.16 CoO 2 , the thickness d modulates in the range of 1.91 ≤ d ≤ 2.04 Å, about 1.96 Å on average. The average d value, 1.96 Å, is shorter than that measured for non-doped orthorhombic (CaOH) 1.14 CoO 2 (Co 2.94+ , d ≈ 2.05 Å), , but is longer than the superconducting sodium cobalt oxides, such as Na 0.343 (H 3 O) 0.237 CoO 2 ·1.19H 2 O (BLH-Na x CoO 2 ( P 2): Co 3.43+ , d ≈ 1.80 Å) or Na 0.35 (H 3 O) 0.17 (H 2 O) 1.22 CoO 2 (BLH-Na x CoO 2 ( P 3): Co 3.48+ , d ≈ 1.85 Å) …”

“…Motivated by this hypothesis we searched for a new member to the layered cobalt oxide family. Recently, two new cobalt calcium hydroxides were synthesized for the first time using the solid-state reaction method at a high temperature and pressure. − These two new materials are (CaOH) 1.14 CoO 2 , which exhibits an orthorhombic lattice structure, and (Ca 0.85 OH) 1.16 CoO 2 , which exhibits a monoclinic lattice structure, where the orthorhombic phase is a polytype of the monoclinic phase.…”