International Tables for Crystallography (2006). Voł. A, Space group 28, pp. 224-225.
Pma 2
Patterson symmetry Pmmm
Pma2
♦— 1 |
—♦— i |
—♦ |
1 i £ ? |
i ♦ i |
1 ♦ i |
1 ♦— |
1 —♦— |
I —t |
n |
PI cm f |
f |
£ j : : i i i i | ||
i |
1 |
I |
r
*o |
*o | |
o* | ||
o* | ||
-o |
*0 | |
♦o |
*o |
Origin on lo2
Asymmetric unit 0 <* < J; 0 < y < 1; 0 < z < 1 Symmetry operations
(1) 1 (2) 2 0,0,z (3) a x,0,z (4) m ),y,z
CONTINUED
Pma 2
Generatora selected (1); f(l,0,0); /(0,1,0); /(0,0,1); (2); (3) Positions
Multiplicity, Coordinates
Wyckoff letter,
Site symmetry
Symmetry of special projections
Along [001] p2mg a' = a b = b
Origin at 0,0, z
Along [100] plml a' = b b’ = c Origin at *,0,0
Along [010] pllm a' = c b' = Origin at0,y,0
Reflection conditions General:
4 |
d 1 |
(D*,y,z |
(2) x,y,z |
(3) |
(t)Z+i,y,z |
II II S| |
Special: as above, plus | ||||||
2 |
c m.. |
!,y>z |
no extra conditions | |||
2 |
b ..2 |
o,i,z |
5, Z |
hkl : h = 2n | ||
2 |
a ..2 |
0,0,Z |
5,0, Z |
hkl : h = 2n |
Maximal non-isomorphic subgroups
I [2] Pio 1 (Pc, 7) 1; 3
[2]Pmll(Pm,6) 1; 4 [2]PI 12(P2,3) 1; 2
na nonę
nb [2] Pba2<b' = 2b) (32); [2] Pmn2x (t = 2c) (31); [2] Pcn2 (ć = 2c) (Pnc2,30); [2]Pco2, (c' = 2c) (29);
[2]Aea2(b' = 2b,ć = 2c)(41); [2]Amo2(b' = 2b,c' = 2c)(40)
Maximal isomorphic subgroups of lowest index
He [2] Pma 2 (b' = 2b) (28); [2] Pm o 2 (C = 2c) (28); [3] Pma2 (a' = 3a) (28)
Minimal non-isomorphic supergroups
I [2] Pccm(49); [2]Pmma(51); [2] Pmna(53); [2] Pbcm(57)
D [2] Cmm2 (35); [2J Bme2 (Aem2, 39); [2] Amo2 (40); [2] Ima2 (46); [2] Pmm2 (a' = ±a)(25)
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