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Title: Phase transitions of cesium azide at pressures up to 30 GPa studied using in situ Raman spectroscopy

Cesium azide has been studied by Raman spectroscopy at pressures up to ≈30 GPa at room temperature. The sequence of phase transitions to Phase III (at 0.5 GPa), Phase IV (at 4.3 GPa), and Phase V (at ≈19 GPa) has been observed in agreement with recent X-ray diffraction studies. Phase III has been found to adopt a monoclinic C2/m structure with two azide anions in nonequivalent positions, where one set of azide anions appears to be orientationally disordered according to the observed Raman spectra. The transition to Phase IV has been associated with orientational ordering of azide anions, while the transition to Phase V has been shown to proceed with a lowering of crystal symmetry. Moreover, spectroscopic features indicate a possible change of bonding in CsN{sub 3} toward formation of covalent bonds at high pressures.
Authors:
;  [1] ;  [1] ;  [2] ;  [1] ;  [2] ;  [3] ; ;  [4]
  1. Max-Planck-Institute for Chemical Physics of Solids, Nöthnitzer-Str. 40, 01187 Dresden (Germany)
  2. (Russian Federation)
  3. Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland)
  4. Energetic Materials Research, Ludwig-Maximilian University Munich (LMU), Butenandtstrasse 5-13(D), D-81377 Munich (Germany)
Publication Date:
OSTI Identifier:
22402957
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 16; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANIONS; AZIDES; CESIUM; CESIUM NITRIDES; CHEMICAL BONDS; CRYSTALS; MONOCLINIC LATTICES; PHASE TRANSFORMATIONS; PRESSURE DEPENDENCE; PRESSURE RANGE GIGA PA; RAMAN SPECTRA; RAMAN SPECTROSCOPY; SYMMETRY; TEMPERATURE RANGE 0273-0400 K; X-RAY DIFFRACTION