CN↓ radi↓ 12 8 3 12)6 4 12 BCC FCC CN of BCC: 8(a)+6(a) CN of FCC: 12(a) 0.290nm 7= aB 4 0.364nm 0.12557nm 0.128674nmCN radii BCC FCC CN of BCC:8( )+6(a) CN of FCC:12( ) rα= = rβ= = = 0.12557nm = 0.128674nm a 2 3 a 2 2  a 4 3 0.290nm 4 3   a 4 2 0.364nm 4 2 