Pmc21 jpeg

International Tabies for Crystaflography (2008), Vol. A, Space group 26, pp. 220-221.

Pmc2_x

No. 26

r²

^2v

Pmc2_l

f- i	—i i
? i	f i

n

mm2    Orthorhombic

Patterson symmetry Pmmm

Pm2,b

P2,an

n

1 1	^ bo	O^ł	bo
! 1 1 1 1 1	1 bO 1 1	O*	bO
1 1 1 1 i 1	I 1 1 bo	o*	bO
1 1	_1 bO	o*	b©

Origin on mc2,

Asymmetric unit 0<;t<j; 0<y<j; 0<z<l Symmetry operations

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

CONTINUED

No. 26

Pmc 2,

Generators selected (ł); i(l,0,0); /(0,1,0); *(0,0,1); (2); (3)

Positions
Multiplicity, Wyckoff letter,	Coordinates		Reflection conditions
Site symmetry			General:
4. c 1 (1) x,y,z	(2 )x,y,z+k (3)x,y,z+±	(4) x,y,2	MU: l- 2 n 00/ : 1 = 2n
			Special: no extra conditions
2 b m.. i,y,z	5^+3
2 a m.. 0 ,y,z	0,y,z + :
Symmetry of special projections
Ałong [001] p2mm	Along [100] plgl		Along [010] pl Im a' = ]c b'=a
a' = a b' = b	a' = b b' = c
Origin at 0,0,z	Origin at*,0,0		Origin at 0,y,0
Maximal non-isomorphic subgroups
I [2}Plcl(Pc,7) 1	l; 3
[2] P mil (Pm, 6) 1	L; 4
[21^112,(^2,, 4) 1	t; 2
Ila nonę

Ilb [2]Pmn2_t (a' = 2a) (31); [2] Pbc2, (b' = 2b) (Pca2,, 29); [2}Cmc2, (a' = 2a,b' - 2b) (36)

Maximal isomorphic subgroups of łowest index

Uc [2] Pmc2, (a' = 2a) (26); [2] Pmc2, (b' = 2b) (26); [3] Pmc2, (c' = 3c) (26)

Minima! non-isomorphic supergroups

I    [2] Pm ma (51); [2] Pbam (55); [2] Pb cm (57); [2] Pnma (62)

U [2]Cmc2, (36); [2] A mm 2 (38); [2}Bme2(Aem2, 39); [2]/ma2(46); [2}Pmm2(ć = £c)(25)

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