CONTINUED No. 12 C2/m
B112/m
UNIQUE AXIS c, CELL CHOICE 2
Origin at centre (2/m)
Asymmetric unit 0 ≤ x ≤ 1; 0 ≤ y ≤
1
2
;0≤ z ≤
1
4
Generators selected (1); t(1, 0,0); t(0,1,0); t(0,0,1); t(
1
2
,0,
1
2
); (2); (3)
Positions
Multiplicity,
Wyckoff letter,
Site symmetry
Coordinates
(0,0, 0)+ (
1
2
,0,
1
2
)+
Reflection conditions
General:
8 j 1(1)x,y, z (2) ¯x, ¯y,z (3) ¯x, ¯y, ¯z (4) x,y, ¯zhkl: h + l = 2n
hk0: h = 2n
0kl : l = 2n
h0l : h + l = 2n
00l : l = 2n
h00 : h = 2n
Special: as above, plus
4 im x,y, 0¯x, ¯y,0 no extra conditions
4 h 2
1
2
,
1
2
,z
1
2
,
1
2
, ¯z 4 g 20,0,z 0,0, ¯z no extra conditions
4 f
¯
1
3
4
,
1
2
,
1
4
1
4
,
1
2
,
1
4
4 e
¯
1
1
4
,0,
1
4
3
4
,0,
1
4
hkl : h = 2n
2 d 2/m
1
2
,
1
2
,
1
2
2 c 2/m
1
2
,
1
2
,0 no extra conditions
2 b 2/ m 0,0,
1
2
2 a 2/ m 0,0,0 no extra conditions
I 112/m
UNIQUE AXIS c, CELL CHOICE 3
Origin at centre (2/m)
Asymmetric unit 0 ≤ x ≤ 1; 0 ≤ y ≤
1
2
;0≤ z ≤
1
4
Generators selected (1); t(1, 0,0); t(0,1,0); t(0,0,1); t(
1
2
,
1
2
,
1
2
); (2); (3)
Positions
Multiplicity,
Wyckoff letter,
Site symmetry
Coordinates
(0,0, 0)+ (
1
2
,
1
2
,
1
2
)+
Reflection conditions
General:
8 j 1(1)x,y, z (2) ¯x, ¯y,z (3) ¯x, ¯y, ¯z (4) x,y, ¯zhkl: h + k + l = 2n
hk0: h + k = 2n
0kl : k + l = 2n
h0l : h + l = 2n
00l : l = 2n
h00 : h = 2n
0k0: k = 2n
Special: as above, plus
4 im x,y, 0¯x, ¯y
,0 no extra conditions
4 h 20,
1
2
,z 0,
1
2
, ¯z 4 g 20,0,z 0,0, ¯z no extra conditions
4 f
¯
1
3
4
,
1
4
,
1
4
1
4
,
3
4
,
1
4
4 e
¯
1
3
4
,
3
4
,
1
4
1
4
,
1
4
,
1
4
hkl : l = 2n
2 d 2/m 0,
1
2
,
1
2
2 c 2/m 0,
1
2
,0 no extra conditions
2 b 2/ m 0,0,
1
2
2 a 2/ m 0,0,0 no extra conditions
175