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Metastable Layered Cobalt Chalcogenides from Topochemical Deintercalation



Xiuquan Zhou, Brandon Wilfong, Hector Vivanco, Johnpierre Paglione, Craig Brown, Efrain E. Rodriguez


We present a general strategy to synthesize metastable layered materials via topochemical de-intercalation of thermodynamically stable to phases.Through kinetic control of the de-intercalation reaction, we have prepared two hypothesized metastable compounds, CoSe and CoS, with the anti-PbO type structure from the starting compounds K1-xCo2-ySe2 and K1-xCo2-yS2, respectively. Thermal stability, crystal structure from X-ray and neutron diffraction, magnetic susceptibility, magnetization, and electrical resistivity are studied for these new layered chalcogenides; both CoSe and CoS are found to be weak itinerant ferromagnets with Curie temperatures close to 10 K. Due to the weak van der Waals forces between the layers, CoSe is found to be a suitable host for further intercalation of guests species such as Li-ethylenediamine. From first-principles calculations, we explain why the Co chalcogenides are ferromagnetic instead of superconducting as in their iron analogues. Bonding analysis of the calculated electronic density of states both explains their phase stability and predicts the limits of our de-intercalation technique. Our results have broad implications of the rational design of new two-dimensional building blocks for functional materials.
Journal of American Chemical Society


crystallography, materials synthesis, powder diffraction


Zhou, X. , Wilfong, B. , Vivanco, H. , Paglione, J. , Brown, C. and Rodriguez, E. (2016), Metastable Layered Cobalt Chalcogenides from Topochemical Deintercalation, Journal of American Chemical Society, [online], (Accessed April 20, 2024)
Created November 28, 2016, Updated October 12, 2021