2cm 2mm Orthorhombic No. 19 2cm Patterson symmetry mmm

Origin on 2c1

 Asymmetric unit 0 ≤ z ≤ 1/4

Symmetry operations

 (1)  1      (1 | 0, 0, 0) (2)  2   x, 0, 0      (2x | 0, 0, 0) (3)  c   x, 0, z      (my | 0, 0, 1/2) (4)  m   x, y, 1/4      (mz | 0, 0, 1/2)

Generators selected (1); t(0, 0, 1); (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, -y, z + 1/2 (4) x, y, -z + 1/2
l: l = 2n
Special: no extra conditions
 2 b . . m
 x, y, 1/4 x, -y, 3/4
 2 a 2 . .
 x, 0, 0 x, 0, 1/2

Symmetry of special projections

 Along [001]   11mOrigin at 0, 0, z Along [100]   2mga' = c   Origin at x, 0, 0 Along [010]   1m1a' = 1/2c   Origin at 0, y, 0

Maximal non-isotypic non-enantiomorphic subgroups

 I [2] 11m (10) 1; 4 [2] 1c1 (c11, 5) 1; 3 [2] 211 (3) 1; 2
 IIa none
 IIb none

Maximal isotypic subgroups and enantiomorphic subgroups of lowest index

 IIc [3] 2cm (c' = 3c) (19)

Minimal non-isotypic non-enantiomorphic supergroups

 I [2] ccm (21); [2] mcm (22); [3] -6c2 (72)
 II [2] 2mm (c' = 1/2c) (18)