Figure 4. Three efficiently packed, inter-penetrating, self-consistent clusters in the Al₂₅La₅₅Ni₂₀ BMG.

The three atoms outlined by dashed lines and connected by triangles are each the centres of one cluster and are in the first shells of the other two clusters, and so are common to all three clusters. The partial and total coordination numbers are: Z_AlAl=2, Z_AlLa=7, Z_AlNi=3, Z_Al,tot=12 for the Al-centred cluster; Z_LaAl=4, Z_LaLa=8, Z_LaNi=3, Z_La,tot=15 for La-centred clusters; and Z_NiAl=3, Z_NiLa=6, Z_NiNi=1, Z_Ni,tot=10 for Ni-centred clusters. These partial coordination numbers are self-consistent, allowing clusters to inter-penetrate with local (cluster) compositions that equal the bulk composition. The relative atom sizes combine with the glass composition and partial coordination numbers to give efficient local packing around all three atom species simultaneously.