Pnc2 C2v6 mm2 Orthorhombic info
No. 30 Pnc2 Patterson symmetry Pmmm

symmetry group diagram

Origin on n 1 2

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

Symmetry operations

(1)  1   (2)  2   0, 0, z(3)  c   x, 1/4, z(4)  n(0, 1/2, 1/2)   0, y, z

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) x, y, z(2) -x, -y, z(3) x, -y + 1/2, z + 1/2(4) -x, y + 1/2, z + 1/2
0kl : k + l = 2n
h0l : l = 2n
0k0 : k = 2n
00l : l = 2n
    Special: as above, plus
2 b  . . 2 
1/2, 0, z 1/2, 1/2, z + 1/2
hkl : k + l = 2n
2 a  . . 2 
0, 0, z 0, 1/2, z + 1/2
hkl : k + l = 2n

Symmetry of special projections

Along [001]   p2gm
a' = a   b' = b   
Origin at 0, 0, z		Along [100]   c1m1
a' = b   b' = c   
Origin at x, 0, 0		Along [010]   p11m
a' = 1/2c   b' = a   
Origin at 0, y, 0

Maximal non-isomorphic subgroups

I [2] P1c1 (Pc, 7)1; 3
  [2] Pn11 (Pc, 7)1; 4
  [2] P112 (P2, 3)1; 2
IIa none
IIb[2] Pnn2 (a' = 2a) (34)

Maximal isomorphic subgroups of lowest index

IIc[2] Pnc2 (a' = 2a) (30); [3] Pnc2 (b' = 3b) (30); [3] Pnc2 (c' = 3c) (30)

Minimal non-isomorphic supergroups

I[2] Pban (50); [2] Pnna (52); [2] Pmna (53); [2] Pbcn (60)
II[2] Ccc2 (37); [2] Amm2 (38); [2] Bbe2 (Aea2, 41); [2] Ima2 (46); [2] Pcc2 (b' = 1/2b) (27); [2] Pbm2 (c' = 1/2c) (Pma2, 28)








































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