pm2a m2m Orthorhombic/Rectangular No. 31 pm2a Patterson symmetry pmmm

Origin on 12a

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

Symmetry operations

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

Symmetry of special projections

 Along [001]   p1m1 a' = 1/2a   b' = b    Origin at 0, 0, z Along [100]   11m a' = b    Origin at x, 0, 0 Along [010]   2mg a' = a    Origin at 0, y, 0

Maximal non-isotypic subgroups

 I [2] pm11 (11) 1; 4 [2] p121 (p211, 8) 1; 2 [2] p11a (5) 1; 3
 IIa none
 IIb [2] pb2n (b' = 2b) (34); [2] pb21a (b' = 2b) (33); [2] pm21n (b' = 2b) (32)

Maximal isotypic subgroups of lowest index

 IIc [2] pm2a (b' = 2b) (31); [3] pm2a (a' = 3a) (31)

Minimal non-isotypic supergroups

 I [2] pmaa (38); [2] pmma (41)
 II [2] cm2e (36); [2] pm2m (a' = 1/2a) (27)