P21212 D23 222 Orthorhombic info
No. 18 P21212 Patterson symmetry Pmmm

symmetry group diagram

Origin at intersection of 2 with perpendicular plane containing 21 axes

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

Symmetry operations

(1)  1   (2)  2   0, 0, z(3)  2(0, 1/2, 0)   1/4y, 0(4)  2(1/2, 0, 0)   x1/4, 0

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 c 1
(1) xyz(2) -x-yz(3) -x + 1/2y + 1/2-z(4) x + 1/2-y + 1/2-z
h00: h = 2n
0k0: k = 2n
    Special: as above, plus
2 b  . . 2 
0, 1/2z 1/2, 0, -z
hk0: h  +  k  =  2n
2 a  . . 2 
0, 0, z 1/21/2-z
hk0: h  +  k  =  2n

Symmetry of special projections

Along [001]   p2gg
a' = a   b' = b   
Origin at 0, 0, z
Along [100]   p2mg
a' = b   b' = c   
Origin at x1/4, 0
Along [010]   p2gm
a' = c   b' = a   
Origin at 1/4y, 0








































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