pb21a m2m Orthorhombic/Rectangular
No. 33 pb21a Patterson symmetry pmmm

symmetry group diagram

Origin on 121a

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

Symmetry operations

(1)  1
      (1 | 0, 0, 0)
(2)  2 (0, 1/2, 0)   0, y, 0
      (2y | 0, 1/2, 0)
(3)  a   xy, 0
      (mz | 1/2, 0, 0)
(4)  b   1/4yz
      (mx | 1/21/2, 0)

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

Positions

Multiplicity, Wyckoff letter,
Site symmetry
Coordinates Reflection conditions

  General:
4 a 1
(1) xyz (2) -xy + 1/2-z (3) x + 1/2y-z (4) -x + 1/2y + 1/2z
hk: h = 2n
h0: h = 2n
0k: k = 2n

Symmetry of special projections

Along [001]   p1g1
a' = 1/2a   b' = b   
Origin at 0, 0, z
Along [100]   [script p]11m
a' = 1/2b   
Origin at x, 0, 0
Along [010]   [script p]2mg
a' = a   
Origin at 0, y, 0

Maximal non-isotypic subgroups


I [2] pb11 (12) 1; 4
  [2] p1211 (p2111, 9) 1; 2
  [2] p11a (5) 1; 3
IIa none
IIb none

Maximal isotypic subgroups of lowest index


IIc [3] pb21a (a' = 3a) (33); [3] pb21a (b' = 3b) (33)

Minimal non-isotypic supergroups


I [2] pbaa (43); [2] pbma (45)
II [2] cm2e (36); [2] p21am (a' = 1/2a) (pb21m, 29); [2] pm2a (b' = 1/2b) (31)








































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