High-pressure Synthesis of Cobalt Polynitrides: Unveiling Intriguing Crystal Structures and Nitridation Behavior

Huawei Chen; Maxim Bykov; Iskander G Batyrev; Lukas Brüning; Elena Bykova; Mohammad F Mahmood; Stella Chariton; Vitali B Prakapenka; Timofey Fedotenko; Hanns-Peter Liermann; Konstantin Glazyrin; Andrew Steele; Alexander F Goncharov

doi:10.1002/chem.202400536

High-pressure Synthesis of Cobalt Polynitrides: Unveiling Intriguing Crystal Structures and Nitridation Behavior

Chemistry. 2024 Mar 25:e202400536. doi: 10.1002/chem.202400536. Online ahead of print.

Authors

Affiliations

¹ Department of Mathematics, Howard University, Washington, DC, 20059, U.S.A.
² The Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, 20015, U.S.A.
³ Institute of Inorganic and Analytical Chemistry, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438, Frankfurt am Main, Germany.
⁴ U.S. Army Research Laboratory RDRLWML-B Aberdeen Proving Ground, Maryland, 21005, U.S.A.
⁵ Institute of Inorganic Chemistry, University of Cologne, Greinstrasse, 50939, Cologne, Germany.
⁶ Institute of Geosciences, Goethe University Frankfurt, Altenhöferallee 1, 60438, Frankfurt am Main, Germany.
⁷ Center for Advanced Radiation Sources, University of Chicago, Argonne, IL 60439, U.S.A.
⁸ Deutsches Elektronene-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany.

PMID: 38527310
DOI: 10.1002/chem.202400536

Abstract

In this study, we conduct extensive high-pressure experiments to investigate phase stability in the cobalt-nitrogen system. Through a combination of synthesis in a laser-heated diamond anvil cell, first-principles calculations, Raman spectroscopy, and single-crystal X-ray diffraction, we establish the stability fields of known high-pressure phases, hexagonal NiAs-type CoN, and marcasite-type CoN₂ within the pressure range of 50-90 GPa. We synthesize and characterize previously unknown nitrides, Co₃N₂, Pnma-CoN and two polynitrides, CoN₃ and CoN₅, within the pressure range of 90-120 GPa. Both polynitrides exhibit novel types of polymeric nitrogen chains and networks. CoN₃ feature branched-type nitrogen trimers (N₃) and CoN₅ show π-bonded nitrogen chain. As the nitrogen content in the cobalt nitride increases, the CoN₆ polyhedral frameworks transit from face-sharing (in CoN) to edge-sharing (in CoN₂ and CoN₃), and finally to isolated (in CoN₅). Our study provides insights into the intricate interplay between structure evolution, bonding arrangements, and high-pressure synthesis in polynitrides, expanding the knowledge for the development of advanced energy materials.

Keywords: Cobalt; Crystal Structure; Diamond-Anvil Cell; High-Pressure; Polynitride.