p-42m -42m Tetragonal/Square
No. 57 p-42m Patterson symmetry p4/mmm

symmetry group diagram

Origin at -42m

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

Symmetry operations

(1)  1    (2)  2   0, 0, z (3)  -4+   0, 0, z; 0, 0, 0 (4)  -4-   0, 0, z; 0, 0, 0
(5)  2   0, y, 0 (6)  2   x, 0, 0 (7)  m   x-xz (8)  m   xxz

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

Positions

Multiplicity, Wyckoff letter,
Site symmetry
Coordinates Reflection conditions

  General:
8 j 1
(1) xyz (2) -x-yz (3) y-x-z (4) -yx-z
(5) -xy-z (6) x-y-z (7) -y-xz (8) yxz
no conditions
    Special:
4 i  . . m 
xxz -x-xz x-x-z -xx-z
no extra conditions
4 h  2 . . 
0, 1/2z 1/2, 0, -z 0, 1/2-z 1/2, 0, z
hk: h + k = 2n
4 g  . 2 . 
x1/2, 0 -x1/2, 0 1/2-x, 0 1/2x, 0
no extra conditions
4 f  . 2 . 
x, 0, 0 -x, 0, 0 0, -x, 0 0, x, 0
no extra conditions
2 e  2 . mm 
1/21/2z 1/21/2-z
no extra conditions
2 d  2 . mm 
0, 0, z 0, 0, -z
no extra conditions
2 c  2 22 . 
1/2, 0, 0 0, 1/2, 0
hk: h + k = 2n
1 b  -4 2 m 
1/21/2, 0
no extra conditions
1 a  -4 2 m 
0, 0, 0
no extra conditions

Symmetry of special projections

Along [001]   p4mm
a' = a   b' = b   
Origin at 0, 0, z
Along [100]   [script p]2mm
a' = b   
Origin at x, 0, 0
Along [110]   [script p]1m1
a' = 1/2(-a + b)   
Origin at xx, 0

Maximal non-isotypic subgroups


I [2] p-411 (p-4, 50) 1; 2; 3; 4
  [2] p21m (cmm2, 26) 1; 2; 7; 8
  [2] p221 (p222, 19) 1; 2; 5; 6
IIa none
IIb [2] c-42d (a' = 2ab' = 2b) (p-4b2, 60); [2] c-42m (a' = 2ab' = 2b) (p-4m2, 59)

Maximal isotypic subgroups of lowest index


IIc [9] p-42m (a' = 3ab' = 3b) (57)

Minimal non-isotypic supergroups


I [2] p4/mmm (61); [2] p4/nbm (62)
II [2] c-42m (p-4m2, 59)








































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