Origin at -1 on 21
| Asymmetric unit | 0 ≤ x ≤ 1; 0 ≤ y ≤ 1; 0 ≤ z ≤ 1/4 |
| (1) 1 | (2) 2(0, 0, 1/2) 0, 0, z | (3) -1 0, 0, 0 | (4) m x, y, 1/4 |
Generators selected (1); t(1, 0, 0); t(0, 1, 0); t(0, 0, 1); (2); (3)
Multiplicity, Wyckoff letter,
Site symmetry | Coordinates | Reflection conditions |
| | | General:
|
| | (1) x, y, z | (2) -x, -y, z + 1/2 | (3) -x, -y, -z | (4) x, y, -z + 1/2 |
| 00l : l = 2n
|
| | | Special: as above, plus
|
| | no extra conditions |
| | 1/2, 1/2, 0 | 1/2, 1/2, 1/2 |
| hkl : l = 2n
|
| | hkl : l = 2n
|
| | hkl : l = 2n
|
| | hkl : l = 2n
|
Symmetry of special projections
Along [001] p2
a' = a b' = b
Origin at 0, 0, z | Along [100] p2gm
a' = bp b' = c
Origin at x, 0, 0 | Along [010] p2mg
a' = c b' = ap
Origin at 0, y, 0 |
Maximal non-isomorphic subgroups
| I | | [2] P11m (Pm, 6) | 1; 4 |
| | | [2] P1121 (P21, 4) | 1; 2 |
| | | [2] P-1 (2) | 1; 3 |
| IIb | [2] P1121/a (a' = 2a) (P21/c, 14); [2] P1121/b (b' = 2b) (P21/c, 14); [2] C1121/e (a' = 2a, b' = 2b) (P21/c, 14) |
Maximal isomorphic subgroups of lowest index
| IIc | [2] P1121/m (a' = 2a or b' = 2b or a' = a - b, b' = a + b) (P21/m, 11); [3] P1121/m (c' = 3c) (P21/m, 11) |
Minimal non-isomorphic supergroups
| I | [2] Pmma (51); [2] Pbcm (57); [2] Pmmn (59); [2] Pnma (62); [2] Cmcm (63); [3] P63/m (176) |
| II | [2] A112/m (C2/m, 12); [2] B112/m (C2/m, 12); [2] I112/m (C2/m, 12); [2] P112/m (c' = 1/2c) (P2/m, 10) |
