[Zurück]

O. Sologub, L. Salamakha, B. Stöger, P. Rogl, T. Mori, Gaku Eguchi, H. Michor, E. Bauer:
"On the boron rich phases in the Yb-B system";
Journal of Solid State Chemistry, 255 (2017), S. 172 - 177.

Two boron rich phases were successfully synthesized by borothermal reduction of Yb oxide under vacuum. For the new boron-poorer phase, the single phase was established at around [B]/[Yb] = 43.3 at 1500 °C (Pbam space group; YB50-type; a = 16.5811(5) Å, b = 17.5950(5) Å, c = 9.4647(3) Å; powder X-ray diffraction; Rietveld refinement). The crystal structure of the boron-richer phase ([B]/[Yb] = 56.7) has been elucidated by single crystal X-ray diffraction (Fm3c space group; YB66-type; a = 23.3587(6) Å). Powder X-ray diffraction data of the
alloy YbB~70 annealed at 1825 °C yielded, along with the YB66-type compound (a = 23.3691(2) Å), β-rh B as a secondary phase (R3m space group, a = 10.9298(3) Å, c = 23.875(1) Å), for which the solubility of Yb was found to be below 1 at%. The Yb atoms in β-rh B occupy the D and E voids. Both YbB43.3 (YB50-type) and YbB56.7 (YB66-type) feature complicated boron atom frameworks which exhibit shorter B-B separations both within and between boron clusters as compared to those observed for prototype structures.

Rare-earth borides, Boron icosahedral framework, Crystal structure, X-ray diffraction

http://dx.doi.org/10.1016/j.jssc.2017.08.007