CONTINUED No. 197 I 23
Generators selected (1); t(1, 0,0); t(0,1,0); t(0,0,1); t(
1
2
,
1
2
,
1
2
); (2); (3); (5)
Positions
Multiplicity,
Wyckoff letter,
Site symmetry
Coordinates
(0,0, 0)+ (
1
2
,
1
2
,
1
2
)+
Reflection conditions
h,k,l cyclically permutable
General:
24 f 1(1)x,y,z (2) ¯x, ¯y,z (3) ¯x,y, ¯z (4) x, ¯y, ¯z
(5) z,x,y (6) z, ¯x, ¯y (7) ¯z, ¯x, y (8) ¯z, x, ¯y
(9) y,z,x (10) ¯y,z, ¯x (11) y, ¯z, ¯x (12) ¯y, ¯z,x
hkl : h + k
+ l = 2n
0kl : k + l = 2n
hhl : l = 2n
h00 : h = 2n
Special: no extra conditions
12 e 2 .. x,
1
2
,0¯x,
1
2
,00, x,
1
2
0, ¯x,
1
2
1
2
,0, x
1
2
,0, ¯x
12 d 2 .. x,0,0¯x,0, 00,x,00, ¯x,00,0,x 0,0, ¯x
8 c . 3 . x,x,x ¯x, ¯x,x ¯x,x, ¯xx, ¯x, ¯x
6 b 222.. 0,
1
2
,
1
2
1
2
,0,
1
2
1
2
,
1
2
,0
2 a 23. 0,0,0
Symmetry of special projections
Along [001] c2mm
a
= ab
= b
Origin at 0,0,z
Along [111] p3
a
=
1
3
(2a − b− c) b
=
1
3
(−a + 2b − c)
Origin at x,x , x
Along [110] p1m1
a
=
1
2
(−a + b) b
=
1
2
c
Origin at x,x , 0
Maximal non-isomorphic subgroups
I
[3] I 21 (I 222, 23) (1; 2; 3; 4)+
⎧
⎪
⎨
⎪
⎩
[4] I 13 (R3, 146) (1; 5; 9)+
[4] I 13 (R3, 146) (1; 6; 12)+
[4] I 13 (R3, 146) (1; 7; 10)+
[4] I 13 (R3, 146) (1; 8; 11)+
IIa [2] P23 (195) 1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12
IIb none
Maximal isomorphic subgroups of lowest index
IIc
[27] I 23(a
= 3a,b
= 3b,c
= 3c) (197)
Minimal non-isomorphic supergroups
I
[2] Im
¯
3 (204); [2] I 432 (211); [2] I
¯
43m (217)
II [4] P23(a
=
1
2
a,b
=
1
2
b,c
=
1
2
c) (195)
609