Precise Lattice Parameters of Selected Rare Earth Tetra- and Hexa-borides1

摘要: Refractory tetraborides and hexaborides of seven the rsre earth elements were prepared by heating intimate mixtures sesquioxide boron in a high vacuum tantalum molybdenum, or graphite crucibles. Preparatory procedures varied until single phase samples obtained. The analyzed chemical x-ray diffraction procedures. Precise lattice parameters obtained analytical extrapolation using digital computer. Some new phases unknown composition structure observed. results indicate pronounced difference between trends their parameters. show nearly linear decrease through series, but an irregular decrease. (auth)