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Title: Crystal structure and thermal expansion of a CsCe{sub 2}Cl{sub 7} scintillator

We used single-crystal X-ray diffraction data to determine crystal structure of CsCe{sub 2}Cl{sub 7}. It crystallizes in a P112{sub 1}/b space group with a=19.352(1) Å, b=19.352(1) Å, c=14.838(1) Å, γ=119.87(2)°, and V=4818.6(5) Å{sup 3}. Differential scanning calorimetry measurements combined with the structural evolution of CsCe{sub 2}Cl{sub 7} via X-ray diffractometry over a temperature range from room temperature to the melting point indicates no obvious intermediate solid–solid phase transitions. The anisotropy in the average linear coefficient of thermal expansion of the a axis (21.3×10{sup –6}/°C) with respect to the b and c axes (27.0×10{sup –6}/°C) was determined through lattice parameter refinement of the temperature dependent diffraction patterns. These findings suggest that the reported cracking behavior during melt growth of CsCe{sub 2}Cl{sub 7} bulk crystals using conventional Bridgman and Czochralski techniques may be largely attributed to the anisotropy in thermal expansion. - Graphical abstract: Three-dimensional quadric surface of thermal expansion coefficient of CsCe{sub 2}Cl{sub 7} at room temperature (sphere – isotropic) and near melting point (ellipsoid – anisotropic). - Highlights: • Crystal structure of CsCe{sub 2}Cl{sub 7} was solved through X-ray diffraction. • Linear coefficients of thermal expansion were determined from in-situ XRD in 25–650 °C. • Anisotropy of the a axismore » with respect to b and c axes (21.3 vs 27.0×10{sup –6}/°C) was found. • No solid–solid phase transitions were observed via XRD and thermal analysis.« less
Authors:
 [1] ;  [2] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ; ;  [6] ;  [1] ;  [2]
  1. Scintillation Materials Research Center, University of Tennessee, Knoxville, TN (United States)
  2. (United States)
  3. Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37996 (United States)
  4. Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)
  5. Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)
  6. Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL (United States)
Publication Date:
OSTI Identifier:
22475692
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 227; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANISOTROPY; CALORIMETRY; CERIUM CHLORIDES; CESIUM COMPOUNDS; CRYSTAL GROWTH; LATTICE PARAMETERS; MELTING POINTS; MONOCRYSTALS; PHASE TRANSFORMATIONS; SURFACES; TEMPERATURE DEPENDENCE; THERMAL ANALYSIS; THERMAL EXPANSION; THREE-DIMENSIONAL LATTICES; X-RAY DIFFRACTION