The phase transitions in cesium azide: Temperature and pressure dependent Raman studies

Iqbal, Zafar; Christoe, C. W.

doi:10.1063/1.430876

Cited by 36 publications

(14 citation statements)

References 18 publications

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“…The space groups of these three structures are same with previous experimental works. 18,31 The resulted atomic fractional coordinates are summarized in Table I and the crystal structures are plotted in Fig. 1.…”

Section: Resultsmentioning

confidence: 99%

Polymerization of nitrogen in cesium azide under modest pressure

Wang

Zhu

et al. 2014

The Journal of Chemical Physics

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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 CsN3 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, P21/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 N3 (-) (linear chains of three N atoms with covalent bonds and interact weakly with each other) begin to show remarkable polymeric N properties in the CsN3 system. Throughout the stable pressure range, the structure is metallic and consists of N atoms in sp(2) hybridizations. Our study completes the structural evolution of CsN3 under pressure and reveals that the introduced Cs atoms are responsible for the decreased synthesis pressure comparing to pure molecular nitrogen under compression.

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Section: Resultsmentioning

confidence: 99%

Polymerization of nitrogen in cesium azide under modest pressure

Wang

Zhu

et al. 2014

The Journal of Chemical Physics

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“…Alkali azides, a comparably stable species among inorganic azides, exhibits a variety of phase transitions stimulated by either temperature or pressure [9][10][11][12][13][14][15][16][17][18][19][20] . During these phases, the behavior of the azide anions N 3 is noticeable.…”

Section: Introductionmentioning

confidence: 99%

“…During these phases, the behavior of the azide anions N 3 is noticeable. In the temperature-induced phase transitions of both rubidium azide (RbN 3 ) and cesium azide (CsN 3 ), a fluctuation of the orientation of N 3 anions was shown [11][12][13] . In both the pressure- 10 and temperature-induced [18][19][20] phase transition of sodium azide (NaN 3 ), a tilting of N 3 anions also exhibits.…”

Section: Introductionmentioning

confidence: 99%

Series of phase transitions in cesium azide under high pressure studied byin situx-ray diffraction

Hou

Zhang

et al. 2011

Phys. Rev. B

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In situ X-ray diffraction measurements of cesium azide (CsN 3) were performed at high pressures up to 55.4 GPa at room temperature. Three phase transitions were revealed as follows: tetragonal (I4/mcm, Phase II) → monoclinic (C2/m, Phase III) → monoclinic (P2 1 /m or P2 1 , Phase IV) → triclinic (P1 or P 1 , Phase V), at 0.5 GPa, 4.4 GPa, and 15.4 GPa, respectively. During the II-III phase transition, CsN 3 keeps its layered structure; and the azide anions rotate obviously. The compressibility of Phase II is dominated by the repulsions between azide anions. The deformation of unit cell is isotropic in Phase II and IV, and anisotropic in Phase III. With increasing pressures, the monoclinic angle increases in Phase III and then becomes stable in Phase IV. The bulk moduli of Phase II, III, IV, and V are determined to be 18 ± 4 GPa, 20 ± 1 GPa, 27 ± 1 GPa and 34 ± 1 GPa, respectively. The ionic character of alkali azides is found to play a key role in their pressure-induced phase transitions.

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“…In the temperatureinduced tetragonal-cubic phase transitions of both rubidium azide (RbN 3 ) and cesium azide (CsN 3 ), a fluctuation of the orientation of N 3 À anions was observed. [16][17][18] In both the temperature- 15 and pressure-induced [23][24][25] rhombohedral-monoclinic phase transition of sodium azide (NaN 3 ), a tilting of N 3 À anions was also observed. High-pressure studies on metal azides are of special interest recently because of their use as a precursor to form a highly energetic polymeric (non-molecular) form of nitrogen (N 2 ).…”

Section: Introductionmentioning

confidence: 99%

“…[12][13][14] Metal azides undergo a variety of pressure or temperatureinduced phase transitions, a phenomenon which has been intensively studied. [14][15][16][17][18][19][20][21][22][23][24][25] The behavior of the azide anions (N 3 À ) during the phase transition is noticeable. In the temperatureinduced tetragonal-cubic phase transitions of both rubidium azide (RbN 3 ) and cesium azide (CsN 3 ), a fluctuation of the orientation of N 3 À anions was observed.…”

Section: Introductionmentioning

confidence: 99%

Phase transition and structure of silver azide at high pressure

Hou

Zhang

et al. 2011

Journal of Applied Physics

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Abstractilver azide (AgN 3 ) was compressed up to 51.3 GPa. The results reveal a reversible second-order orthorhombic-to-tetragonal phase transformation starting from ambient pressure and completing at 2.7 GPa. The phase transition is accompanied by a proximity of cell parameters aand b, a 3° rotation of azide anions, and a change of coordination number from 4-4 (four short, four long) to eight fold. The crystal structure of the high pressure phase is determined to be inI4/mcm space group, with Ag at 4a, N 1 at 4d, and N 2 at 8h Wyckoff positions. Both of the two phases have anisotropic compressibility: the orthorhombic phase exhibits an anomalous expansion under compression along a-axis and is more compressive along b-axis than c-axis; the tetragonal phase is more compressive along the interlayer direction than the intralayer directions. The bulk moduli of the orthorhombic and tetragonal phases are determined to be K OT = 39 ± 5 GPa with K OT ' = 10 ± 7 and K OT = 57 ± 2 GPa with K OT ' = 6.6 ± 0.2, respectively. KeywordsMechanical Engineering, Materials Science and Engineering, High pressure, Phase transitions, Active galaxies, Silver, Equations of state, X-ray diffraction, Polymers, Anisotropy, Elastic moduli, Magmatic magnetic minerals Disciplines Aerospace Engineering | Materials Science and Engineering | Mechanical Engineering CommentsThe following article appeared in Journal of Applied Physics 110 (2011) Silver azide (AgN 3 ) was compressed up to 51.3 GPa. The results reveal a reversible second-order orthorhombic-to-tetragonal phase transformation starting from ambient pressure and completing at 2.7 GPa. The phase transition is accompanied by a proximity of cell parameters a and b, a 3 rotation of azide anions, and a change of coordination number from 4-4 (four short, four long) to eight fold. The crystal structure of the high pressure phase is determined to be in I4/mcm space group, with Ag at 4a, N 1 at 4d, and N 2 at 8h Wyckoff positions. Both of the two phases have anisotropic compressibility: the orthorhombic phase exhibits an anomalous expansion under compression along a-axis and is more compressive along b-axis than c-axis; the tetragonal phase is more compressive along the interlayer direction than the intralayer directions. The bulk moduli of the orthorhombic and tetragonal phases are determined to be K OT ¼ 39 6 5 GPa with K OT ' ¼ 10 6 7 and K OT ¼ 57 6 2 GPa with K OT ' ¼ 6.6 6 0.2, respectively.

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The phase transitions in cesium azide: Temperature and pressure dependent Raman studies

Cited by 36 publications

References 18 publications

Polymerization of nitrogen in cesium azide under modest pressure

Polymerization of nitrogen in cesium azide under modest pressure

Series of phase transitions in cesium azide under high pressure studied byin situx-ray diffraction

Phase transition and structure of silver azide at high pressure

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