pm2m m2m Orthorhombic/Rectangular No. 27 pm2m Patterson symmetry pmmm

Origin on m2m

 Asymmetric unit 0 ≤ x ≤ 1/2; 0 ≤ y ≤ 1; 0 ≤ z

Symmetry operations

 (1)  1 (2)  2   0, y, 0 (3)  m   0, y, z (4)  m   x, y, 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 f 1
 (1) x, y, z (2) -x, y, -z (3) -x, y, z (4) x, y, -z
no conditions
Special: no extra conditions
 2 e . . m
 x, y, 0 -x, y, 0
 2 d m . .
 1/2, y, z 1/2, y, -z
 2 c m . .
 0, y, z 0, y, -z
 1 b m 2 m
 1/2, y, 0
 1 a m 2 m
 0, y, 0

Symmetry of special projections

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

Maximal non-isotypic subgroups

 I [2] pm11 (11) 1; 3 [2] p121 (p211, 8) 1; 2 [2] p11m (4) 1; 4
 IIa none
 IIb [2] cm2e (a' = 2a, b' = 2b) (36); [2] cm2m (a' = 2a, b' = 2b) (35); [2] pm2a (a' = 2a) (31); [2] pb2b (b' = 2b) (30); [2] pb21m (b' = 2b) (29); [2] pm21b (b' = 2b) (28)

Maximal isotypic subgroups of lowest index

 IIc [2] pm2m (a' = 2a) (27); [2] pm2m (b' = 2b) (27)

Minimal non-isotypic supergroups

 I [2] pmmm (37); [2] pmam (40); [3] p-6m2 (78); [3] p-62m (79)
 II [2] cm2m (35)