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Title: Exotic stable cesium polynitrides at high pressure

New polynitrides containing metastable forms of nitrogen are actively investigated as potential high energy-density materials. Using a structure search method based on the CALYPSO methodology, we investigated the stable stoichiometries and structures of cesium polynitrides at high pressures. Along with the CsN3, we identified five new stoichiometric compounds (Cs3N, Cs2N, CsN, CsN2, and CsN5) with interesting structures that may be experimentally synthesizable at modest pressures (i.e., less than 50 GPa). Nitrogen species in the predicted structures have various structural forms ranging from single atom (N) to highly endothermic molecules (N2, N3 , N4, N5, N6) and chains (N). Polymeric chains of nitrogen were found in the high-pressure C2/c phase of CsN2. This structure contains a substantially high content of single N-N bonds that exceeds the previously known nitrogen chains in pure forms, and also exhibit metastability at ambient conditions. We also identified a very interesting CsN crystal that contains novel N44- anion. In conclusion, to our best knowledge, this is the first time a charged N4 species being reported. Results of the present study suggest that it is possible to obtain energetic polynitrogens in main-group nitrides under high pressure.
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Luoyang Normal University, Luoyang (China). College of Physics and Electronic Information,; Beijing Computational Science Research Center, Beijing (China)
  2. Luoyang Normal University, Luoyang (China). College of Physics and Electronic Information
  3. Carnegie Inst. of Washington, Washington, DC (United States). Geophysical Lab.
  4. Univ. of Saskatchewan, Saskatoon, SK (Canada). Department of Physics and Engineering Physics; Canadian Light Sources, Inc., Saskatoon, SK (Canada)
Publication Date:
OSTI Identifier:
1241100
Grant/Contract Number:
SC-0001057; NA-0002006
Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 5; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Research Org:
Carnegie Inst. of Washington, Washington, DC (United States). Geophysical Lab.
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY