| P21 | No. 4 | C22 |
| P1211 | P1121 | |||||
|
UNIQUE AXIS b |
UNIQUE AXIS c |
|||||
| Wyckoff | ||||||
| Axes | Coordinates | positions | Axes | Coordinates | ||
| 2a | ||||||
| I Maximal translationengleiche subgroups | ||||||
| [2] P1 (1) | 2 × 1a | P1 | ||||
| II Maximal klassengleiche subgroups | ||||||
| Enlarged unit cell, isomorphic | ||||||
| [3] P1211 | a, 3b, c | x, (1/3)y, z; ±(0, (1/3), 0) | 3 × 2a | P1121 | a, b, 3c | x, y, (1/3)z; ±(0, 0, (1/3)) |
| [p] P1211 | a, pb, c | x, (1/p)y, z; +(0, (u/p), 0) | p × 2a | P1121 | a, b, pc | x, y, (1/p)z; +(0, 0, (u/p)) |
| p = prime > 2; u = 1, . . ., p - 1 | p = prime > 2; u = 1, . . ., p - 1 | |||||
| [2] P1211 | 2a, b, c | (1/2)x, y, z; +((1/2), 0, 0) | 2 × 2a | P1121 | a, 2b, c | x, (1/2)y, z; +(0, (1/2), 0) |
| [2] P1211 | 2a, b, c | (1/2)x + (1/4), y, z; +((1/2), 0, 0) | 2 × 2a | P1121 | a, 2b, c | x, (1/2)y + (1/4), z; +(0, (1/2), 0) |
| [2] P1211 | a - c, b, a + c | (1/2)(x - z), y, (1/2)(x + z); +((1/2), 0, (1/2)) | 2 × 2a | P1121 | a + b, -a + b, c | (1/2)(x + y), (1/2)(-x + y), z; +((1/2), (1/2), 0) |
| or: | a - c, b, 2c | x, y, (1/2)(x + z); +(0, 0, (1/2)) | or: | 2a, -a + b, c | (1/2)(x + y), y, z; +((1/2), 0, 0) | |
| [2] P1211 | a - c, b, a + c | (1/2)(x - z) + (1/4), y, (1/2)(x + z) + (1/4); +((1/2), 0, (1/2)) | 2 × 2a | P1121 | a + b, -a + b, c | (1/2)(x + y) + (1/4), (1/2)(-x + y) + (1/4), z; +((1/2), (1/2), 0) |
| or: | a - c, b, 2c | x, y, (1/2)(x + z) + (1/4); +(0, 0, (1/2)) | or: | 2a, -a + b, c | (1/2)(x + y) + (1/4), y, z; +((1/2), 0, 0) | |
| [2] P1211 | a, b, 2c | x, y, (1/2)z; +(0, 0, (1/2)) | 2 × 2a | P1121 | 2a, b, c | (1/2)x, y, z; +((1/2), 0, 0) |
| [2] P1211 | a, b, 2c | x, y, (1/2)z + (1/4); +(0, 0, (1/2)) | 2 × 2a | P1121 | 2a, b, c | (1/2)x + (1/4), y, z; +((1/2), 0, 0) |
| [3] P1211 | 3a, b, c | (1/3)x, y, z; ±((1/3), 0, 0) | 3 × 2a | P1121 | a, 3b, c | x, (1/3)y, z; ±(0, (1/3), 0) |
| [3] P1211 | 3a, b, -a + c | (1/3)(x + z), y, z; ±((1/3), 0, 0) | 3 × 2a | P1121 | a - b, 3b, c | x, (1/3)(x + y), z; ±(0, (1/3), 0) |
| [3] P1211 | 3a, b, a + c | (1/3)(x - z), y, z; ±((1/3), 0, 0) | 3 × 2a | P1121 | a + b, 3b, c | x, (1/3)(-x + y), z; ±(0, (1/3), 0) |
| [3] P1211 | a, b, 3c | x, y, (1/3)z; ±(0, 0, (1/3)) | 3 × 2a | P1121 | 3a, b, c | (1/3)x, y, z; ±((1/3), 0, 0) |
| [p] P1211 | a, b, pc | x, y, (1/p)z; +(0, 0, (u/p)) | p × 2a | P1121 | pa, b, c | (1/p)x, y, z; +((u/p), 0, 0) |
| p = prime; u = 1, . . ., p - 1 | p = prime; u = 1, . . ., p - 1 | |||||
| [p] P1211 | pa, b, qa + c | (1/p)(x - qz), y, z; +((u/p), 0, 0) | p × 2a | P1121 | a + qb, pb, c | x, (1/p)(-qx + y), z; +(0, (u/p), 0) |
| p = prime; u = 1, . . ., p - 1; | p = prime; u = 1, . . ., p - 1; | |||||
| -(1/2)(p - 1)≤ q ≤ (1/2)(p - 1) | -(1/2)(p - 1)≤ q ≤ (1/2)(p - 1) | |||||
