CONTINUED No. 22 F 222
Generators selected (1); t(1, 0,0); t(0,1,0); t(0,0,1); t(0,
1
2
,
1
2
); t(
1
2
,0,
1
2
); (2); (3)
Positions
Multiplicity,
Wyckoff letter,
Site symmetry
Coordinates
(0,0, 0)+ (0,
1
2
,
1
2
)+ (
1
2
,0,
1
2
)+ (
1
2
,
1
2
,0)+
Reflection conditions
General:
16 k 1(1)x, y,z (2) ¯x, ¯y,z (3) ¯x,y, ¯z (4) x, ¯y, ¯zhkl: h + k,h + l,k + l = 2n
0kl : k,l = 2n
h0l : h, l = 2n
hk0: h, k = 2n
h00 : h = 2n
0k0: k = 2n
00l : l = 2n
Special: no extra conditions
8 j
2 .. x,
1
4
,
1
4
¯x,
3
4
,
1
4
8 i . 2 .
1
4
,y,
1
4
3
4
, ¯y,
1
4
8 h ..2
1
4
,
1
4
,z
3
4
,
1
4
, ¯z
8 g ..20, 0,z 0,0, ¯z
8 f . 2 . 0, y,00, ¯y,0
8 e 2 .. x,0, 0¯x,0,0
4 d 222
1
4
,
1
4
,
3
4
4 c 222
1
4
,
1
4
,
1
4
4 b 222 0,0,
1
2
4 a 222 0,0,0
Symmetry of special projections
Along [001] p2mm
a
=
1
2
ab
=
1
2
b
Origin at 0,0,z
Along [100] p2mm
a
=
1
2
bb
=
1
2
c
Origin at x,0,0
Along [010] p2mm
a
=
1
2
cb
=
1
2
a
Origin at 0,y, 0
Maximal non-isomorphic subgroups
I
[2] F 112(C2, 5) (1; 2)+
[2] F 121(C2, 5) (1; 3)+
[2] F 211(C2, 5) (1; 4)+
IIa [2] A222 (C222, 21) 1; 2; 3; 4; (1; 2; 3; 4)+(0,
1
2
,
1
2
)
[2] A222 (C222, 21) 1; 4; (1; 4)+(0,
1
2
,
1
2
); (2; 3)+(
1
2
,0,
1
2
); (2; 3)+(
1
2
,
1
2
,0)
[2] B222 (C222, 21) 1; 2; 3; 4; (1; 2; 3; 4)+(
1
2
,0,
1
2
)
[2] B222 (C222, 21) 1; 3; (1; 3)+(
1
2
,0,
1
2
); (2; 4)+(
1
2
,
1
2
,0); (2; 4)+(0,
1
2
,
1
2
)
[2] C 222 (21) 1; 2; 3; 4; (1; 2; 3; 4)+(
1
2
,
1
2
,0)
[2] C 222 (21) 1; 2; (1; 2)+(
1
2
,
1
2
,0); (3; 4)+(0,
1
2
,
1
2
); (3; 4)+(
1
2
,0,
1
2
)
[2] A2
1
22(C222
1
, 20) 1; 2; (1; 2)+(0,
1
2
,
1
2
); (3; 4)+(
1
2
,0,
1
2
); (3; 4)+(
1
2
,
1
2
,0)
[2] A2
1
22(C222
1
, 20) 1; 3; (1; 3)+(0,
1
2
,
1
2
); (2; 4)+(
1
2
,0,
1
2
); (2; 4)+(
1
2
,
1
2
,0)
[2] B22
1
2(C 222
1
, 20) 1; 2; (1; 2)+(
1
2
,0,
1
2
); (3; 4)+(
1
2
,
1
2
,0); (3; 4)+(0,
1
2
,
1
2
)
[2] B22
1
2(C 222
1
, 20) 1; 4; (1; 4)+(
1
2
,0,
1
2
); (2; 3)+(
1
2
,
1
2
,0); (2; 3)+(0,
1
2
,
1
2
)
[2] C 222
1
(20) 1; 3; (1; 3)+(
1
2
,
1
2
,0); (2; 4)+(0,
1
2
,
1
2
); (2; 4)+(
1
2
,0,
1
2
)
[2] C 222
1
(20) 1; 4; (1; 4)+(
1
2
,
1
2
,0); (2; 3)+(0,
1
2
,
1
2
); (2; 3)+(
1
2
,0,
1
2
)
IIb none
(Continued on preceding page)
213