Structural study of a new B-rich phase obtained by partial hydrogenation of 2NaH+MgB2

作者:Pistidda Claudio*; Napolitano Emilio; Pottmaier Daphiny; Dornheim Martin; Klassen Thomas; Baricco Marcello; Enzo Stefano
来源:International Journal of Hydrogen Energy, 2013, 38(25): 10479-10484.
DOI:10.1016/j.ijhydene.2013.06.025

摘要

The structure of an unknown crystalline phase observed during the hydrogen absorption reaction of the powder mixtures 2NaH + MgB2 at high pressure has been studied by ab-initio structure determination from powder diffraction. The sequence of un-overlapped peaks extracted from the X-ray powder diffraction pattern could be indexed with a primitive cubic cell with lattice parameter a = 7.319 angstrom. The diffraction patterns of the peaks are matched with the Pa-3 space group. The stoichiometry of the hydrogen absorption reaction suggests the presence of a high-boron content phase in the compound under investigation. Assuming this phase to be composed only by boron atoms and therefore having a density similar to that found for boron polymorphs, the solution with a space group of Pa-3 leads to reasonable B-B interatomic distances.

  • 出版日期2013-8-21