Metastable Layered Cobalt Chalcogenides from Topochemical Deintercalation

Published

November 29, 2016

Author(s)

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

Abstract

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 K_1-xCo_2-ySe₂ and K_1-xCo_2-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.

Citation

Journal of American Chemical Society

Volume

138

Issue

50

Pub Type

Journals

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Keywords

crystallography, materials synthesis, powder diffraction

Citation

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], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=922062 (Accessed October 2, 2025)