* o \*o 0o^ o Y P,.O


 o \ o o










 *0 Mo Open circles: atoms in first and
 third layers
 S Ni Closed circles: atoms in second
 layer




 Figure 2.7 Two dimensional representation of Dla
 stacking showing 1.) FCC unit cell ( ),
 2.) Dla unit cell (-- -), and 3.) 420 FCC
 stacking sequence (----).