The system Ce–Zn–B at 800 °C

The isothermal section for the system Ce–Zn–B has been established at 800 °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 βCe2Zn17 above ∼750 °C with the Th2Zn17 type (R3̄m, a=0.90916(4) nm, c=1.3286(1) nm) and low temperature αCeZn7 (Ce1−xZn5+2x; x∼0.33) up to 750 °C for which we attributed the TbCu7 type (P6/mmm, a=0.52424(2), c=0.44274(1) nm). The crystal structure of CeZn7 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: Ce3Zn11 (Immm, a=0.45242(2) nm, b=0.88942(3) nm, c=1.34754(4) nm) and Ce3Zn22 (I41/amd; a=0.89363(2) nm, c=2.1804(5) nm).