Le Bail fits to synchrotron x-ray powder diffraction patterns from CDP measured at different temperatures under ambient pressure. The open symbols are the observed intensities , the solid line is the best fit , and the lower trace is the difference curve . The vertical bars indicate the positions of the Bragg reflections. A transition from the room-temperature monoclinic phase (; , , , and ) to a high-temperature cubic phase (; ) occurs at .
Temperature dependence of the lattice parameters and unit cell volume of the monoclinic CDP phase obtained from Le Bail fits to x-ray diffraction data. The lattice parameters vary smoothly with , indicating that the RT monoclinic phase persists up to .
Rietveld refinement of the high-temperature cubic CDP phase. The empty symbols show the scattered intensity as a function of the diffraction angle , while the solid line represents the calculated pattern. The lower trace is the difference between the observed and the calculated patterns and the vertical bars are the Bragg reflection markers. The inset shows one of the six possible orientations of the tetrahedra and the corresponding hydrogen-bond network (dashed lines). The Cs atoms are omitted for clarity.
Time-resolved synchrotron x-ray powder diffraction patterns of CDP measured at under ambient pressure. The data evidence the slow and partial decomposition of the cubic CDP phase via dehydration according to the reaction .
Synchrotron x-ray powder diffraction patterns from CDP heated under high pressure to , , and . The two data sets at were collected at different times, apart. The vertical bars indicate the -spacing positions of the Brag reflections from the cubic CDP phase (; ), whereas the vertical arrows mark the positions of three strong reflections from . The peaks marked by M and C indicate the strongest reflections from the monoclinic and cubic CDP phase. The crosses and squares mark the fluorescence lines from cesium and tungsten, respectively. The inset shows the best Rietveld fit (solid line) to the x-ray diffraction data collected at (crosses)—several -spacing intervals had to be excluded due to the presence of strong fluorescence peaks. The vertical bars in the inset mark the -spacing positions of the Bragg reflections, while the lover trace is the difference between the observed and the calculated patterns.
Fractional atomic coordinates and thermal parameters in the high-temperature CDP phase. Numbers in parentheses are statistical estimated standard deviations from the Rietveld fit.
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