p2mm 2mm Rectangular No. 6 p2mm Patterson symmetry p2mm

Origin at 2 m m

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

Symmetry operations

 (1)  1 (2)  2   0, 0 (3)  m   0, y (4)  m   x, 0

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

Positions

Multiplicity, Wyckoff letter,
Site symmetry
Coordinates Reflection conditions

General:
 4 i 1
 (1) x, y (2) -x, -y (3) -x, y (4) x, -y
no conditions
Special: as above, plus
 2 h . m .
 1/2, y 1/2, -y
no extra conditions
 2 g . m .
 0, y 0, -y
no extra conditions
 2 f . . m
 x, 1/2 -x, 1/2
no extra conditions
 2 e . . m
 x, 0 -x, 0
no extra conditions
 1 d 2 m m
 1/2, 1/2
no extra conditions
 1 c 2 m m
 1/2, 0
no extra conditions
 1 b 2 m m
 0, 1/2
no extra conditions
 1 a 2 m m
 0, 0
no extra conditions

Maximal non-isomorphic subgroups

 I [2] p1m1 (pm, 3) 1; 3 [2] p11m (pm, 3) 1; 4 [2] p211 (p2, 2) 1; 2
 IIa none
 IIb [2] p2mg (a' = 2a) (7); [2] p2gm (b' = 2b) (p2mg, 7); [2] c2mm (a' = 2a, b' = 2b) (9)

Maximal isomorphic subgroups of lowest index

 IIc [2] p2mm (a' = 2a or b' = 2b) (6)

Minimal non-isomorphic supergroups

 I [2] p4mm (11)
 II [2] c2mm (9)