fig1

Figure 1. (A) Nb supercell BCC structure containing non-equivalent substitutional models of X_Nb0Y_Nb1 and X_Nb0Y_Nb2; (B) α-Nb₅Si₃ BCT conventional cell containing four non-equivalent sites: Nb_I, Nb_II, Si_I, and Si_II. The M (subscripts I) and L (subscripts II) represent the more and less closely packed layers, respectively. BCC: Body-centered cubic; BCT: body-centered tetragonal.