pma2 mm2 Orthorhombic/Rectangular No. 24 pma2 Patterson symmetry pmmm

Origin on 1a2

 Asymmetric unit 0 ≤ x ≤ 1/4; 0 ≤ y ≤ 1

Symmetry operations

 (1)  1       (1 | 0, 0, 0) (2)  2   0, 0, z       (2z | 0, 0, 0) (3)  a   x, 0, z       (my | 1/2, 0, 0) (4)  m   1/4, y, z       (mx | 1/2, 0, 0)

Generators selected (1); t(1, 0, 0); t(0, 1, 0); (2); (3)

Positions

Multiplicity, Wyckoff letter,
Site symmetry
Coordinates Reflection conditions

General:
 4 d 1
 (1) x, y, z (2) -x, -y, z (3) x + 1/2, -y, z (4) -x + 1/2, y, z
h0: h = 2n
Special: as above, plus
 2 c m . .
 1/4, y, z 3/4, -y, z
no extra conditions
 2 b . . 2
 0, 1/2, z 1/2, 1/2, z
hk: h = 2n
 2 a . . 2
 0, 0, z 1/2, 0, z
hk: h = 2n

Symmetry of special projections

 Along [001]   p2mg a' = a   b' = b    Origin at 0, 0, z Along [100]   1m1 a' = b    Origin at x, 0, 0 Along [010]   1m1 a' = 1/2a    Origin at 0, y, 0

Maximal non-isotypic subgroups

 I [2] p1a1 (pb11, 12) 1; 3 [2] pm11 (11) 1; 4 [2] p112 (3) 1; 2
 IIa none
 IIb [2] pba2 (b' = 2b) (25)

Maximal isotypic subgroups of lowest index

 IIc [2] pma2 (b' = 2b) (24); [3] pma2 (a' = 3a) (24)

Minimal non-isotypic supergroups

 I [2] pmaa (38); [2] pmam (40); [2] pman (42); [2] pbma (45)
 II [2] cmm2 (26); [2] pmm2 (a' = 1/2a) (23)