2. FCC O EXample: Y-Fe, Al, Ni, Pb, Cu Ag,Au, stainless steal°t。 ②n=8×1/8+6×12=4 atoms/cel 3 CN=12 4√2 4×-丌 34 0.742. FCC  Example: γ-Fe , Al , Ni , Pb , Cu , Ag , Au , stainless steal  n= 8×1/8+6×1/2=4 atoms/cell  CN=12  0.74 ) 4 2 ( 3 4 4 3 3 =  = a  