A New Yttrium Boride: YB 25

A new yttrium boride has been found to exist between YB₁₂and YB₅₀. A single phase was established at a nominal composition of [B]/[Y]=25.5-26.0. X ray powder diffraction and electron diffraction analyses showed that the new YB₂₅phase has a monoclinic system witha=0.82842(3) nm,b=1.03203(3) nm,c=0.58570(2) nm,β=90.402(3)°, and space groupI121(No. 5),I1m1 (No. 8), orI12/m1 (No. 12). Rare earth elements from Gd to Ho can also form compounds isostructural to YB₂₅.