Examples:

Xa structure, FeCo1.5Ti0.5Ge

X1 = [Fe,Sites.b4,1.0]    		#1 atom			#set as SG216 structure!
X2 = [Co,Sites.d4,1.0] 			#1 atom
Y1 = [Co,Sites.c4,0.5]			#1 atom
Y2 = [Ti,Sites.c4,0.5]			#1 atom
Z1 = [Ge,Sites.a4,0.5]			#1 atom
Z2 = [Ge,Sites.a4,0.5]			#1 atom

L21 Cu2MnAl

X1 = [Cu,Sites.c8,0.5]    		#2 atoms			#set as SG225 structure!
X2 = [Cu,Sites.c8,0.5] 			#2 atoms
Y1 = [Mn,Sites.b4,0.5]			#1 atom
Y2 = [Mn,Sites.b4,0.5]			#1 atom
Z1 = [Al,Sites.a4,0.5]			#1 atom
Z2 = [Al,Sites.a4,0.5]			#1 atom


DO19 Fe2MnGe

X1 = [Fe,Sites.h6,2.0/3]   	#set as SG194 structure above! define x & z above!
X2 = [Fe,Sites.h6,0] 		#as long as X1+X2 occupancy adds up right ...
Y1 = [Mn,Sites.h6,1.0/3]
Y2 = [Mn,Sites.h6,0]
Z1 = [Ge,Sites.d2,1.0]
Z2 = [Ge,Sites.d2,0]

fcc Al

X1 = [Al,Sites.a4,0.5]		#set as SG225
X2 = [Al,Sites.a4,0.5]		#you do need to define all sites
Y1 = [Al,Sites.a4,0.0]		
Y2 = [Al,Sites.a4,0.0]
Z1 = [Al,Sites.a4,0.0]		
Z2 = [Al,Sites.a4,0.0]

DO3 AlFe3

X1 = [Al,Sites.a4,0.5]   	#set as SG225 structure above! define x & z above!
X2 = [Al,Sites.a4,0.5] 
Y1 = [Fe,Sites.b4,0.5]
Y2 = [Fe,Sites.b4,0.5]
Z1 = [Fe,Sites.8c,1.0]
Z2 = [Fe,Sites.8c,1.0]

DO22 Al3Ti

X1 = [Ti,Sites.a2,1.0]    		#1 atom			#set as SG139 structure above!
X2 = [Ti,Sites.a2,0.0] 			#1 atom
Y1 = [Al,Sites.b2,0.5]			#1 atom
Y2 = [Al,Sites.b2,0.5]			#1 atom
Z1 = [Al,Sites.d4,0.5]			#1 atom
Z2 = [Al,Sites.d4,0.5]			#1 atom