The system Ce–Zn–B at 800 °C

The isothermal section for the system Ce-Zn-B has been established at 800 deg. C using electron microprobe analysis and X-ray powder diffraction. No ternary compounds exist and mutual solid solubilities of binary phases are negligible. In the concentration range of 10.0-10.5 at% Ce two structural modifications have been confirmed: high temperature {beta}Ce{sub 2}Zn{sub 17} above {approx}750 deg. C with the Th{sub 2}Zn{sub 17} type (R3-bar m, a=0.90916(4) nm, c=1.3286(1) nm) and low temperature {alpha}CeZn{sub 7} (Ce{sub 1-x}Zn{sub 5+2x}; x{approx}0.33) up to 750 deg. C for which we attributed the TbCu{sub 7} type (P6/mmm, a=0.52424(2), c=0.44274(1) nm). The crystal structure of CeZn{sub 7} was derived from the Rietveld refinement of X-ray powder intensities. Precise data on atom site distribution and positional parameters have been furthermore provided from X-ray single crystal refinements for two compounds, for which crystal structures hitherto have only been derived from X-ray diffraction photographs: Ce{sub 3}Zn{sub 11} (Immm, a=0.45242(2) nm, b=0.88942(3) nm, c=1.34754(4) nm) and Ce{sub 3}Zn{sub 22} (I4{sub 1}/amd; a=0.89363(2) nm, c=2.1804(5) nm). - Graphical abstract: Existence of low temperature modification {alpha}CeZn{sub 7} (Ce{sub 1-x}Zn{sub 5+2x}; x{approx}0.33) of Ce{sub 2}Zn{sub 17} has been verified up to 750 deg. C that is attributed with the TbCu{sub 7} type.more » Highlights: > Isothermal section of system Ce-Zn-B at 800 deg. C. > In System Ce-Zn, X-ray single crystal intensity data refinement of Ce{sub 3}Zn{sub 11} and Ce{sub 3}Zn{sub 22} and Rietveld refinement of Ce{sub 13}Zn{sub 58}. > Two temperature modifications of Ce{sub 2}Zn{sub 17}, rhombohedral {beta}Ce{sub 2}Zn{sub 17} (hT) and of hexagonal {alpha}CeZn{sub 7} (lT). > No ternary compound in the System Ce-Zn-B (<50 at% Ce) at 800 deg. C.« less