P21/m C2h2 2/m Monoclinic info
No. 11 P121/m1 Patterson symmetry P12/m1
UNIQUE AXIS b

symmetry group diagram

Origin at -1 on 21

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

Symmetry operations

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

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 f 1
(1) xyz(2) -xy + 1/2-z(3) -x-y-z(4) x-y + 1/2z
0k0: k = 2n
    Special: as above, plus
2 e  m 
x1/4z -x3/4-z
no extra conditions
2 d  -1 
1/2, 0, 1/2 1/21/21/2
hkl: k  =  2n
2 c  -1 
0, 0, 1/2 0, 1/21/2
hkl: k  =  2n
2 b  -1 
1/2, 0, 0 1/21/2, 0
hkl: k  =  2n
2 a  -1 
0, 0, 0 0, 1/2, 0
hkl: k  =  2n

Symmetry of special projections

Along [001]   p2gm
a' = ap   b' = b   
Origin at 0, 0, z
Along [100]   p2mg
a' = b   b' = cp   
Origin at x, 0, 0
Along [010]   p2
a' = c   b' = a   
Origin at 0, y, 0





P21/m C2h2 2/m Monoclinic info
No. 11 P1121/m Patterson symmetry P112/m
UNIQUE AXIS c

symmetry group diagram

Origin at -1 on 21

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

Symmetry operations

(1)  1   (2)  2(0, 0, 1/2)   0, 0, z(3)  -1   0, 0, 0(4)  m   xy1/4

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 f 1
(1) xyz(2) -x-yz + 1/2(3) -x-y-z(4) xy-z + 1/2
00l: l = 2n
    Special: as above, plus
2 e  m 
xy1/4 -x-y3/4
no extra conditions
2 d  -1 
1/21/2, 0 1/21/21/2
hkl: l  =  2n
2 c  -1 
1/2, 0, 0 1/2, 0, 1/2
hkl: l  =  2n
2 b  -1 
0, 1/2, 0 0, 1/21/2
hkl: l  =  2n
2 a  -1 
0, 0, 0 0, 0, 1/2
hkl: l  =  2n

Symmetry of special projections

Along [001]   p2
a' = a   b' = b   
Origin at 0, 0, z
Along [100]   p2gm
a' = bp   b' = c   
Origin at x, 0, 0
Along [010]   p2mg
a' = c   b' = ap   
Origin at 0, y, 0








































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