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Title: Polymerization of nitrogen in cesium azide under modest pressure

Alkali metal azides can be used as starting materials in the synthesis of polymeric nitrogen, a potential high-energy-density material. The structural evolutionary behaviors of nitrogen in CsN{sub 3} have been studied up to 200 GPa using particle swarm optimization structure search combining with density functional theory. Three stable new phases with C2/m, P2{sub 1}/m, and P-1 structure at pressure of 6, 13, and 51 GPa are identified for the first time. The phase transition to chain like structure (P-1 phase) occurs at a modest pressure 51 GPa, the azide ions N{sub 3}{sup −} (linear chains of three N atoms with covalent bonds and interact weakly with each other) begin to show remarkable polymeric N properties in the CsN{sub 3} system. Throughout the stable pressure range, the structure is metallic and consists of N atoms in sp{sup 2} hybridizations. Our study completes the structural evolution of CsN{sub 3} under pressure and reveals that the introduced Cs atoms are responsible for the decreased synthesis pressure comparing to pure molecular nitrogen under compression.
Authors:
 [1] ;  [2] ;  [2] ;  [1] ;  [3] ;  [4] ;  [1] ;  [5]
  1. Institute of Condensed Matter Physics, Linyi University, Linyi 276005 (China)
  2. (China)
  3. (Hong Kong)
  4. State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012 (China)
  5. Beijing Computational Science Research Center, Beijing 100084 (China)
Publication Date:
OSTI Identifier:
22419963
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ATOMS; AZIDES; CESIUM; CHEMICAL BONDS; DENSITY FUNCTIONAL METHOD; IONS; MONOCLINIC LATTICES; NITROGEN; PHASE TRANSFORMATIONS; POLYMERIZATION; SYNTHESIS