[script p]mcm mmm Orthorhombic
No. 22 [script p]2/m2/c21/m Patterson symmetry [script p]mmm

symmetry group diagram

Origin at centre (2/m) at 2/mc21

Asymmetric unit 0 ≤ x; 0 ≤ z ≤ 1/4

Symmetry operations

(1)  1
      (1 | 0, 0, 0)
(2)  2   0, y1/4
      (2y | 0, 0, 1/2)
(3)  2   x, 0, 0
      (2x | 0, 0, 0)
(4)  2 (1/2)   0, 0, z
      (2z | 0, 0, 1/2)
(5)  -1   0, 0, 0
      (-1 | 0, 0, 0)
(6)  c   x, 0, z
      (my | 0, 0, 1/2)
(7)  m   0, yz
      (mx | 0, 0, 0)
(8)  m   xy1/4
      (mz | 0, 0, 1/2)

Generators selected (1); t(0, 0, 1); (2); (3); (5)

Positions

Multiplicity, Wyckoff letter,
Site symmetry
Coordinates Reflection conditions

 General:
8 f 1
(1) xyz(2) -xy-z + 1/2(3) x-y-z(4) -x-yz + 1/2
(5) -x-y-z(6) x-yz + 1/2(7) -xyz(8) xy-z + 1/2
no conditions
  Special: no extra conditions
4 e  . . m 
xy1/4-xy1/4x-y3/4-x-y3/4
4 d  m . . 
0, yz0, y-z + 1/20, -y-z0, -yz + 1/2
4 c  2 . . 
x, 0, 0-x, 0, 1/2-x, 0, 0x, 0, 1/2
2 b  m 2 m 
0, y1/40, -y3/4
2 a  2/m . . 
0, 0, 00, 0, 1/2

Symmetry of special projections

Along [001]   2mm

Origin at 0, 0, z
Along [100]   [script p]2mg
a' = c   
Origin at x, 0, 0
Along [010]   [script p]2mm
a' = 1/2c   
Origin at 0, y, 0

Maximal non-isotypic non-enantiomorphic subgroups


I[2] [script p]2cm (19)1; 3; 6; 8
 [2] [script p]m2m ([script p]2mm, 18)1; 2; 7; 8
 [2] [script p]mc21 (17)1; 4; 6; 7
 [2] [script p]2221 (14)1; 2; 3; 4
 [2] [script p]1121/m (12)1; 4; 5; 8
 [2] [script p]12/c1 ([script p]2/c11, 7)1; 2; 5; 6
 [2] [script p]2/m11 (6)1; 3; 5; 7
IIa none
IIbnone

Maximal isotypic subgroups and enantiomorphic subgroups of lowest index


IIc[3] [script p]mcm (c' = 3c) (22)

Minimal non-isotypic non-enantiomorphic supergroups


I[3] [script p]63/mmc (75)
II[2] [script p]mmm (c' = 1/2c) (20)








































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