Origin at -1 on 21
| Asymmetric unit | 0 ≤ x ≤ 1; 0 ≤ y ≤ 1/4; 0 ≤ z ≤ 1 |
| (1) 1 | (2) 2(0, 1/2, 0) 0, y, 0 | (3) -1 0, 0, 0 | (4) m x, 1/4, z |
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 + 1/2, -z | (3) -x, -y, -z | (4) x, -y + 1/2, z |
| 0k0 : k = 2n
|
| | | Special: as above, plus
|
| | no extra conditions |
| | 1/2, 0, 1/2 | 1/2, 1/2, 1/2 |
| hkl : k = 2n
|
| | hkl : k = 2n
|
| | hkl : k = 2n
|
| | hkl : k = 2n
|
Symmetry of special projections
Along [001] p2gm
a' = ap b' = b
Origin at 0, 0, z | Along [100] p2mg
a' = b b' = cp
Origin at x, 0, 0 | Along [010] p2
a' = c b' = a
Origin at 0, y, 0 |
Maximal non-isomorphic subgroups
| I | | [2] P1m1 (Pm, 6) | 1; 4 |
| | | [2] P1211 (P21, 4) | 1; 2 |
| | | [2] P-1 (2) | 1; 3 |
| IIb | [2] P121/c1 (c' = 2c) (P21/c, 14); [2] P121/a1 (a' = 2a) (P21/c, 14); [2] B121/e1 (a' = 2a, c' = 2c) (P21/c, 14) |
Maximal isomorphic subgroups of lowest index
| IIc | [2] P121/m1 (c' = 2c or a' = 2a or a' = a + c, c' = -a + c) (P21/m, 11); [3] P121/m1 (b' = 3b) (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] C12/m1 (C2/m, 12); [2] A12/m1 (C2/m, 12); [2] I12/m1 (C2/m, 12); [2] P12/m1 (b' = 1/2b) (P2/m, 10) |
