Origin at -1 on 2₁

Asymmetric unit

0 ≤ x ≤ 1/4; 0 ≤ y ≤ 1

(1)  1

(2)  2(1/2, 0, 0)   x, 0, 0

(3)  -1   0, 0, 0

(4)  m   1/4, y, 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, -y, -z (4) -x + 1/2, y, z	h0: h = 2n

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

Symmetry of special projections

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

Along [100]   211 a' = b    Origin at x, 0, 0

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

Maximal non-isotypic subgroups

---

I	[2] pm11 (11)	1; 4
	[2] p2111 (9)	1; 2
	[2] p-1 (2)	1; 3

IIa

none

IIb	[2] p21/b11 (b' = 2b) (17)

Maximal isotypic subgroups of lowest index

---

IIc	[2] p21/m11 (b' = 2b) (15); [3] p21/m11 (a' = 3a) (15)

Minimal non-isotypic supergroups

---

I	[2] pmam (40); [2] pmma (41); [2] pbma (45); [2] pmmn (46)

II	[2] c2/m11 (18); [2] p2/m11 (a' = 1/2a) (14)

---