Origin at 2₁12

Asymmetric unit

0 ≤ x ≤ 1; 0 ≤ y ≤ 1/2; 0 ≤ z

(1)  1

(2)  2(1/2, 0, 0)   x, 0, 0

(3)  2   1/4, y, 0

(4)  2   0, 0, z

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

Positions

Multiplicity, Wyckoff letter, Site symmetry	Coordinates	Reflection conditions
		General:
4 d 1	(1) x, y, z (2) x + 1/2, -y, -z (3) -x + 1/2, y, -z (4) -x, -y, z	h0: h = 2n

		Special: as above, plus
2 c  . 2 .	1/4, y, 0 3/4, -y, 0	no extra conditions
2 b  . . 2	0, 1/2, z 1/2, 1/2, -z	hk: h = 2n
2 a  . . 2	0, 0, z 1/2, 0, -z	hk: h = 2n

Symmetry of special projections

Along [001]   p2mg a' = a   b' = b    Origin at 0, 0, z

Along [100]   2mm a' = b    Origin at x, 0, 0

Along [010]   2mg a' = a    Origin at 1/4, y, 0

Maximal non-isotypic subgroups

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I	[2] p2111 (9)	1; 2
	[2] p121 (p211, 8)	1; 3
	[2] p112 (3)	1; 4

IIa

none

IIb	[2] p21212 (b' = 2b) (21)

Maximal isotypic subgroups of lowest index

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IIc	[2] p2122 (b' = 2b) (20); [3] p2122 (a' = 3a) (20)

Minimal non-isotypic supergroups

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I	[2] pmam (40); [2] pmma (41); [2] pman (42); [2] pbaa (43); [2] pbma (45)

II	[2] c222 (22); [2] p222 (a' = 1/2a) (19)

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