Imma No. 74 I21/m21/m21/a D2h28


Axes Coordinates Wyckoff positions
4a 4b 4c 4d 4e 8f 8g 8h 8i 16j
I Maximal translationengleiche subgroups
[2] I2mb (46) 4a 4a 4b 4b 4b 2 × 4a 8c 8c 2 × 4b 2 × 8c
[conventional setting]Ima2 b, c, a y, z, x
[2] Im2a (46) x + (1/4), y, z + (1/4) 4b 4b 4a 4a 4b 8c 2 × 4a 2 × 4b 8c 2 × 8c
[conventional setting]Ima2 a, -c, b x + (1/4), -z - (1/4), y
[2] Imm2 (44) x, y + (1/4), z 4d 4d 4c 4c 2a; 2b 8e 8e 2 × 4d 2 × 4c 2 × 8e
[2] I212121 (24) x, y, z + (1/4) 4a 4a 4b 4b 4c 2 × 4a 2 × 4b 8d 8d 2 × 8d
[2] I112/b (15) 4a 4b 4d 4c 4e 8f 8f 8f 8f 2 × 8f
[conventional setting]A112/a b, -a - b, c -x + y, -x, z
[2] I2/m11 (12) 2a; 2d 2b; 2c 4e 4f 4i 4g; 4h 8j 2 × 4i 8j 2 × 8j
[conventional setting]I12/m1 c, a, b z, x, y
[conventional setting]C12/m1 -b - c, a, c -y, x, -y + z
[2] I12/m1 (12) x + (1/4), y + (1/4), z + (1/4) 4e 4f 2a; 2c 2b; 2d 4i 8j 4g; 4h 8j 2 × 4i 2 × 8j
[conventional setting]C12/m1 -a - c, b, a -z - (1/4), y + (1/4), x - z
II Maximal klassengleiche subgroups
   Loss of centring translations
[2] Pnma (62) 4a 4b 4c 4c 4c 8d 8d 8d 2 × 4c 2 × 8d
[2] Pmnb (62) x + (1/4), y + (1/4), z + (1/4) 4c 4c 4a 4b 4c 8d 8d 2 × 4c 8d 2 × 8d
[conventional setting]Pnma b, -a, c y + (1/4), -x - (1/4), z + (1/4)
[2] Pmna (53) 2a; 2d 2b; 2c 4g 4g 4h 4e; 4f 2 × 4g 2 × 4h 8i 2 × 8i
[2] Pnmb (53) x + (1/4), y + (1/4), z + (1/4) 4g 4g 2a; 2d 2b; 2c 4h 2 × 4g 4e; 4f 8i 2 × 4h 2 × 8i
[conventional setting]Pmna b, -a, c y + (1/4), -x - (1/4), z + (1/4)
[2] Pnna (52) x + (1/4), y + (1/4), z + (1/4) 4d 4d 4a 4b 4c 2 × 4d 8e 8e 8e 2 × 8e
[2] Pnnb (52) 4a 4b 4d 4d 4c 8e 2 × 4d 8e 8e 2 × 8e
[conventional setting]Pnna b, -a, c y, -x, z
[2] Pmma (51) x + (1/4), y + (1/4), z + (1/4) 4k 4k 2a; 2d 2b; 2c 2e; 2f 8l 4g; 4h 2 × 4k 4i; 4j 2 × 8l
[2] Pmmb (51) 2a; 2d 2b; 2c 4k 4k 2e; 2f 4g; 4h 8l 4i; 4j 2 × 4k 2 × 8l
[conventional setting]Pmma b, -a, c y, -x, z
   Enlarged unit cell, isomorphic
[3] Imma 3a, b, c (1/3)x, y, z; ±((1/3), 0, 0) 4a; 8f 4b; 8f 4c; 8i 4d; 8i 4e; 8i 3 × 8f 8g; 16j 8h; 16j 3 × 8i 3 × 16j
[p] Imma pa, b, c (1/p)x, y, z; +((u/p), 0, 0) 4a; 4b; 4c; 4d; 4e; p × 8f 8g; 8h; p × 8i p × 16j
p = prime > 2; u = 1, . . ., p - 1 ((p - 1)/2) × 8f ((p - 1)/2) × 8f ((p - 1)/2) × 8i ((p - 1)/2) × 8i ((p - 1)/2) × 8i ((p - 1)/2) × ((p - 1)/2) ×
16j 16j
[3] Imma a, 3b, c x, (1/3)y, z; ±(0, (1/3), 0) 4a; 8h 4b; 8h 4d; 8g 4c; 8g 4e; 8h 8f; 16j 3 × 8g 3 × 8h 8i; 16j 3 × 16j
[p] Imma a, pb, c x, (1/p)y, z; +(0, (u/p), 0) 4a; 4b; 4c(d*); 4d(c*); 4e; 8f; p × 8g p × 8h 8i; p × 16j
p = prime > 2; u = 1, . . ., p - 1 ((p - 1)/2) × 8h ((p - 1)/2) × 8h ((p - 1)/2) × 8g ((p - 1)/2) × 8g ((p - 1)/2) × 8h ((p - 1)/2) × ((p - 1)/2) ×
16j 16j
[3] Imma a, b, 3c x, y, (1/3)z; ±(0, 0, (1/3)) 4a; 8h 4b; 8h 4d; 8i 4c; 8i 3 × 4e 8f; 16j 8g; 16j 3 × 8h 3 × 8i 3 × 16j
[p] Imma a, b, pc x, y, (1/p)z; +(0, 0, (u/p)) 4a; 4b; 4c(d*); 4d(c*); p × 4e 8f; 8g; p × 8h p × 8i p × 16j
p = prime > 2; u = 1, . . ., p - 1 ((p - 1)/2) × 8h ((p - 1)/2) × 8h ((p - 1)/2) × 8i ((p - 1)/2) × 8i ((p - 1)/2) × ((p - 1)/2) ×
16j 16j
* p = 4n - 1


Nonconventional settings
        interchange letters and sequences in Hermann-Mauguin symbols, axes and coordinates:
Ibmm C → A→ B a→ b → c → a a→ b → c → a x→ y → z → x
Imcm A→ C→ B a← b ← c ← a a← b ← c ← a x← y ← z ← x









































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