Origin on 3[111] at midpoint of three non-intersecting pairs of parallel screw axes 41 and 21
Asymmetric unit | -1/4 ≤ x ≤ 1/2; 0 ≤ y ≤ 3/4; 0 ≤ z ≤ 1/2; x ≤ y ≤ x + 1/2; (y - x)/2 ≤ z ≤ min(y, (-4x - 2y + 3)/2, (3 - 2x - 2y)/4) | ||||||
Vertices |
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Symmetry operations
(1) 1 | (2) 2(0, 0, 1/2) 1/4, 0, z | (3) 2(0, 1/2, 0) 0, y, 1/4 | (4) 2(1/2, 0, 0) x, 1/4, 0 |
(5) 3+ x, x, x | (6) 3+ -x + 1/2, x, -x | (7) 3+ x + 1/2, -x - 1/2, -x | (8) 3+ -x, -x + 1/2, x |
(9) 3- x, x, x | (10) 3-(-1/3, 1/3, 1/3) x + 1/6, -x + 1/6, -x | (11) 3-(1/3, 1/3, -1/3) -x + 1/3, -x + 1/6, x | (12) 3-(1/3, -1/3, 1/3) -x - 1/6, x + 1/3, -x |
(13) 2(1/2, 1/2, 0) x, x - 1/4, 1/8 | (14) 2 x, -x + 3/4, 3/8 | (15) 4-(0, 0, 3/4) 1/4, 0, z | (16) 4+(0, 0, 1/4) -1/4, 1/2, z |
(17) 4-(3/4, 0, 0) x, 1/4, 0 | (18) 2(0, 1/2, 1/2) 1/8, y + 1/4, y | (19) 2 3/8, y + 3/4, -y | (20) 4+(1/4, 0, 0) x, -1/4, 1/2 |
(21) 4+(0, 1/4, 0) 1/2, y, -1/4 | (22) 2(1/2, 0, 1/2) x - 1/4, 1/8, x | (23) 4-(0, 3/4, 0) 0, y, 1/4 | (24) 2 -x + 3/4, 3/8, x |
Generators selected (1); t(1, 0, 0); t(0, 1, 0); t(0, 0, 1); (2); (3); (5); (13)
Positions
Multiplicity, Wyckoff letter, Site symmetry | Coordinates | Reflection conditions | |||||||||||||||||||||||||||
h, k, l permutable General: | |||||||||||||||||||||||||||||
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| h00 : h = 4n |
Special: as above, plus | |||||||||||||||||
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| no extra conditions | |||||||||||||||
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| 0kl : k = 2n + 1 or l = 2n + 1 or k + l = 4n | |||||||||||||||
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| hkl : h, k = 2n + 1 or h = 2n + 1, k = 4n and l = 4n + 2 or h, k, l = 4n + 2 or h, k, l = 4n | |||||||||||||||
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Symmetry of special projections
Along [001] p4gm a' = a b' = b Origin at 1/4, 0, z | Along [111] p3m1 a' = 1/3(2a - b - c) b' = 1/3(-a + 2b - c) Origin at x, x, x | Along [110] p2gm a' = 1/2(-a + b) b' = c Origin at x, x + 1/4, 1/8 |
Maximal non-isomorphic subgroups
I | [2] P2131 (P213, 198) | 1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12 | ||||||||||||||
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IIa | none |
IIb | none |
Maximal isomorphic subgroups of lowest index
IIc | [27] P4332 (a' = 3a, b' = 3b, c' = 3c) (212); [125] P4132 (a' = 5a, b' = 5b, c' = 5c) (213) |
Minimal non-isomorphic supergroups
I | none |
II | [2] I4132 (214); [4] F4132 (210) |