Origin on m m 2
| Asymmetric unit | 0 ≤ x ≤ 1/4; 0 ≤ y ≤ 1/2; 0 ≤ z ≤ 1 |
For (0, 0, 0)+ set
| (1) 1 | (2) 2 0, 0, z | (3) m x, 0, z | (4) m 0, y, z |
For (1/2, 1/2, 0)+ set
| (1) t(1/2, 1/2, 0) | (2) 2 1/4, 1/4, z | (3) a x, 1/4, z | (4) b 1/4, y, z |
Generators selected (1); t(1, 0, 0); t(0, 1, 0); t(0, 0, 1); t(1/2, 1/2, 0); (2); (3)
Multiplicity, Wyckoff letter,
Site symmetry | Coordinates | Reflection conditions |
| | (0, 0, 0)+ (1/2, 1/2, 0)+ | General:
|
| | (1) x, y, z | (2) -x, -y, z | (3) x, -y, z | (4) -x, y, z |
| hkl : h + k = 2n
0kl : k = 2n
h0l : h = 2n
hk0 : h + k = 2n
h00 : h = 2n
0k0 : k = 2n
|
| | | Special: as above, plus
|
| | no extra conditions |
| | no extra conditions |
| | hkl : h = 2n
|
| | no extra conditions |
| | no extra conditions |
Symmetry of special projections
Along [001] c2mm
a' = a b' = b
Origin at 0, 0, z | Along [100] p1m1
a' = 1/2b b' = c
Origin at x, 0, 0 | Along [010] p11m
a' = c b' = 1/2a
Origin at 0, y, 0 |
Maximal non-isomorphic subgroups
| I | | [2] C1m1 (Cm, 8) | (1; 3)+ |
| | | [2] Cm11 (Cm, 8) | (1; 4)+ |
| | | [2] C112 (P2, 3) | (1; 2)+ |
| IIa | | [2] Pba2 (32) | 1; 2; (3; 4) + (1/2, 1/2, 0) |
| | | [2] Pbm2 (Pma2, 28) | 1; 3; (2; 4) + (1/2, 1/2, 0) |
| | | [2] Pma2 (28) | 1; 4; (2; 3) + (1/2, 1/2, 0) |
| | | [2] Pmm2 (25) | 1; 2; 3; 4 |
| IIb | [2] Ima2 (c' = 2c) (46); [2] Ibm2 (c' = 2c) (Ima2, 46); [2] Iba2 (c' = 2c) (45); [2] Imm2 (c' = 2c) (44); [2] Ccc2 (c' = 2c) (37); [2] Cmc21 (c' = 2c) (36); [2] Ccm21 (c' = 2c) (Cmc21, 36) |
Maximal isomorphic subgroups of lowest index
| IIc | [2] Cmm2 (c' = 2c) (35); [3] Cmm2 (a' = 3a or b' = 3b) (35) |
Minimal non-isomorphic supergroups
| I | [2] Cmmm (65); [2] Cmme (67); [2] P4mm (99); [2] P4bm (100); [2] P42cm (101); [2] P42nm (102); [2] P-42m (111); [2] P-421m (113); [3] P6mm (183) |
| II | [2] Fmm2 (42); [2] Pmm2 (a' = 1/2a, b' = 1/2b) (25) |
