Pmm2 C2v1 mm2 Orthorhombic info
No. 25 Pmm2 Patterson symmetry Pmmm

symmetry group diagram

Origin on m m 2

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

Symmetry operations

(1)  1   (2)  2   0, 0, z(3)  m   x, 0, z(4)  m   0, yz

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

Positions

Multiplicity, Wyckoff letter,
Site symmetry
Coordinates Reflection conditions
 General:
4 i 1
(1) xyz(2) -x-yz(3) x-yz(4) -xyz
no conditions
    Special: as above, plus
2 h  m . . 
1/2yz 1/2-yz
no extra conditions
2 g  m . . 
0, yz 0, -yz
no extra conditions
2 f  . m . 
x1/2z -x1/2z
no extra conditions
2 e  . m . 
x, 0, z -x, 0, z
no extra conditions
1 d  m m 2 
1/21/2z
no extra conditions
1 c  m m 2 
1/2, 0, z
no extra conditions
1 b  m m 2 
0, 1/2z
no extra conditions
1 a  m m 2 
0, 0, z
no extra conditions

Symmetry of special projections

Along [001]   p2mm
a' = a   b' = b   
Origin at 0, 0, z
Along [100]   p1m1
a' = b   b' = c   
Origin at x, 0, 0
Along [010]   p11m
a' = c   b' = a   
Origin at 0, y, 0








































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