Series of Phase Transitions in Cesium Azide Under High Pressure Studied by in situ X-ray Diffraction

Journal Article · Sat Dec 31 04:00:00 EST 2011 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PhysRevB.84.064127· OSTI ID:1042129

Hou, D; Zhang, F; Ji, C; Hannon, T; Zhu, H; Wu, J; Ma, Y

In situ x-ray diffraction measurements of cesium azide (CsN{sub 3}) were performed at high pressures of up to 55.4 GPa at room temperature. Three phase transitions were revealed as follows: tetragonal (I4/mcm, Phase II) {yields} monoclinic (C2/m, Phase III) {yields} monoclinic (P2{sub 1}/m or P2{sub 1}, Phase IV) {yields} triclinic (P1 or P1{sup -}, Phase V), at 0.5, 4.4, and 15.4 GPa, respectively. During the II-III phase transition, CsN{sub 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 Phases 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 Phases II, III, IV, and V are determined to be 18 {+-} 4, 20 {+-} 1, 27 {+-} 1 and 34 {+-} 1 GPa, respectively. The ionic character of alkali azides is found to play a key role in their pressure-induced phase transitions.

• Research Organization: BROOKHAVEN NATIONAL LABORATORY (BNL)
• Sponsoring Organization: USDOE SC OFFICE OF SCIENCE (SC)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1042129
• Report Number(s): BNL--97807-2012-JA
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 6 Vol. 84; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANIONS
AZIDES
CESIUM
COMPRESSIBILITY
DEFORMATION
X-RAY DIFFRACTION