Pressure-induced phase transitions in rubidium azide: Studied by in-situ x-ray diffraction

Journal Article · Mon Aug 18 04:00:00 EDT 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4893464· OSTI ID:22310873

Li, Dongmei; Wu, Xiaoxin; Jiang, Junru; Zhang, Jian; Cui, Qiliang; Zhu, Hongyang ^[1]; Wang, Xiaoli ^[1]

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1. State Key Laboratory of Superhard Materials, Jilin University, Changchun, Jilin 130012 (China)

We present the in-situ X-ray diffraction studies of RbN{sub 3} up to 42.0 GPa at room temperature to supplement the high pressure exploration of alkali azides. Two pressure-induced phase transitions of α-RbN{sub 3} → γ-RbN{sub 3} → δ-RbN{sub 3} were revealed at 6.5 and 16.0 GPa, respectively. During the phase transition of α-RbN{sub 3} → γ-RbN{sub 3}, lattice symmetry decreases from a fourfold to a twofold axis accompanied by a rearrangement of azide anions. The γ-RbN{sub 3} was identified to be a monoclinic structure with C2/m space group. Upon further compression, an orthogonal arrangement of azide anions becomes energetically favorable for δ-RbN{sub 3}. The compressibility of α-RbN{sub 3} is anisotropic due to the orientation of azide anions. The bulk modulus of α-RbN{sub 3} is 18.4 GPa, quite close to those of KN{sub 3} and CsN{sub 3}. By comparing the phase transition pressures of alkali azides, their ionic character is found to play a key role in pressure-induced phase transitions.

• OSTI ID: 22310873
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 7 Vol. 105; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANISOTROPY
COMPRESSIBILITY
COMPRESSION
EXPLORATION
MONOCLINIC LATTICES
PHASE TRANSFORMATIONS
PRESSURE RANGE GIGA PA
RUBIDIUM
RUBIDIUM NITRATES
SPACE GROUPS
TEMPERATURE RANGE 0273-0400 K
X-RAY DIFFRACTION