New compounds with YCrB4-type structure

This paper investigates part of the Yb- Fe, Co, Ni -B ternary systems to obtain borides with YCrB4-type structure. Compact Yb of 99.94 mass % purity and precompacted powders of finely crystalline boron, Fe, Co, or Ni were fused in an electric-arc furnace in an atmosphere of purified argon. The results of x-ray phase-shift analysis showed that borides with YCrB4-type structure were formed in 11 of the studied systems. The obtained values of the unit-cell parameters for the compounds YbCoB4, YbFeB4, and YbNiB4 are inscribed smoothly in the curve of the change of unit-cell parameters and volumes of RMB4 compounds, which indicates a trivalent state of the ytterbium atoms in these borides