p2mg 2mm Rectangularinfo
No. 7 p2mg Patterson symmetry p2mm

symmetry group diagram

Origin at 2 1 g

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

Symmetry operations

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

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

Positions

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

Maximal non-isomorphic subgroups

I[2] p11g (pg, 4)1; 4
 [2] p1m1 (pm, 3)1; 3
 [2] p211 (p2, 2)1; 2
IIa none
IIb[2] p2gg (b' = 2b) (8)

Maximal isomorphic subgroups of lowest index

IIc[2] p2mg (b' = 2b) (7); [3] p2mg (a' = 3a) (7)

Minimal non-isomorphic supergroups

Inone
II[2] c2mm (9); [2] p2mm(a' = 1/2 a) (6)








































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