P21c jpeg

International Tables for C/ystallography (2006). Vol. A, Space group 14, pp. 184-191,

P2,/c    CL

No. 14    PI 2,/cl

UNIQUE AXIS b, CELL CHOICE 1

2/m    Monoclinic

Patterson symmetry P12/m ł

r;

*	*	s
1 f	o	i o /
f	S	*
cl		1

Origin at 1

Asymmetric unit 0 < jc < 1; 0 < y < *; 0 < z < 1 Symmetry operations

(1) 1    (2) 2(0,5,0) 0,y,i    (3) \ 0,0,0    (4) c x,l,z

Positions
Multiplicity,	Coordinates
Wyckoff letter.
Site symmetry

Reflection conditions General:

4 e 1    (1) jc,y,z    (2)x,>> + ^2 + ^    (3 )x,y,z    (4) x,y+±,z+1    hOl:l=2n

OkO: k = 2n 00/ : / = 2n

Special: as above, plus

2	I	1,0,1	5,5,0	hkl :	k + l = 2n
2	c I	0,0,1	0,1,0	hkl :	k + l = 2n
2	& 1	i,0,0	1,1,5	hkl :	k + l = 2n
2	a 1	0,0,0	0,1,1	hkl :	k+l = 2n

Symmetry of special projections

Along [010] p 2 a' = ;C b' = a Origin at 0,y,0

Along [100] p2gg a' = b b' — c_p Origin at*, 0,0

CONTINUED

No. 14

P2,/c

Generators selected (1); /(1,0,0); /(0,1,0); f(0,0,l); (2); (3)

Along [001] p2gm a' = a b' = b Origin atQ,0,z

Maximal non-isomorphic subgroups

I	[2] Piel (Pc, 7)	1; 4
	[2] PI2,1 (P2,, 4)	1; 2
	[2] P 1(2)	1; 3
Ha	nonę
Hb	nonę

Maximal isomorphic subgroups of lowest index

lic    [2] P12,fc 1 (a' = 2a or a' = 2a,c' = 2a + c)(P2,jc, 14); [3) Plljcl (b' = 3b)(P2, jc, 14)

Minimal non-isomorphic supergroups

I    [2] Pnna (52); [2] Pmna (53); [2] Pcca (54); [2] Pb ant (55); [2] Pccn (56); [2] Pb cm (57); [2] Pnnm( 58); [2] Pbcn (60); [2] Pbca (61); [2] Pnma (62); [2] Cmce (64)

II    [2] A12/m 1 (C2fm, 12); [2] C12/c 1 (C2/c, 15); [2] /12/c 1 (C2/c, 15); [2] P12, /m 1 (c' = ±c) (P2, jm, 11);

[2] P12/c 1 Ob' = jb) (P2/c, 13)

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