The α-AlB12 structure

The crystal structure of α-AlB₁₂, reported recently by Higashi, Sakurai, and Atoda is confirmed by an independent investigation of a different crystal. The space group is P4₁2₁2 (or P4₃2₁2) and our lattice parameters are a = 10.161(7)Å, c = 14.283(8)Å. The structure was partially solved by Patterson methods, when the full structure was communicated to us by Higashi et al. Utilizing 2393 reflections, our structure refinement yields an R value of 2.6% with very low standard deviations for structural parameters (0.0001 for atomic coordinates of boron atoms). Within the standard deviations there is excellent agreement with all parameters determined by Higashi et al. It is found, nevertheless, that the structural parameters of α-AlB₁₂ do not serve to account for the reported Debye-Scherrer patterns of “BeB₆,” “LiB₆,” or β-tetragonal boron, all of which have the same cell dimensions and space group as α-AlB₁₂.