Pcca No. 54 P21/c2/c2/a D2h8


Axes Coordinates Wyckoff positions
4a 4b 4c 4d 4e 8f
I Maximal translationengleiche subgroups
[2] Pc2a (32) x, y, z + (1/4) 4c 4c 2a; 2b 4c 4c 2 × 4c
[conventional setting]Pba2 c, a, b z + (1/4), x, y
[2] P21ca (29) x, y, z + (1/4) 4a 4a 4a 4a 4a 2 × 4a
[conventional setting]Pca21 c, -b, a z + (1/4), -y, x
[2] Pcc2 (27) x + (1/4), y, z 4e 4e 4e 2a; 2c 2b; 2d 2 × 4e
[2] P2122 (17) x, y, z + (1/4) 4e 4e 2a; 2b 2 × 2c 2 × 2d 2 × 4e
[conventional setting]P2221 b, c, a y, z + (1/4), x
[2] P21/c11 (14) 2a; 2c 2b; 2d 4e 4e 4e 2 × 4e
[conventional setting]P121/c1 b, -a, c y, -x, z
[2] P12/c1 (13) 2a; 2d 2b; 2c 2e; 2f 4g 4g 2 × 4g
[2] P112/a (13) 2a; 2c 2b; 2d 4g 2 × 2e 2 × 2f 2 × 4g
II Maximal klassengleiche subgroups
   Enlarged unit cell, non-isomorphic
[2] Pnca (60) a, 2b, c x, (1/2)y, z; +(0, (1/2), 0) 4a; 4b 8d 8d 2 × 4c 8d 2 × 8d
[conventional setting]Pbcn 2b, c, a (1/2)y, z, x; +((1/2), 0, 0)
[2] Pnca (60) a, 2b, c x, (1/2)y + (1/4), z; +(0, (1/2), 0) 8d 4a; 4b 8d 8d 2 × 4c 2 × 8d
[conventional setting]Pbcn 2b, c, a (1/2)y + (1/4), z, x; +((1/2), 0, 0)
[2] Pccn (56) a, 2b, c x, (1/2)y, z; +(0, (1/2), 0) 4a; 4b 8e 8e 8e 4c; 4d 2 × 8e
[2] Pccn (56) a, 2b, c x, (1/2)y + (1/4), z; +(0, (1/2), 0) 8e 4a; 4b 8e 4c; 4d 8e 2 × 8e
[2] Pncn (52) a, 2b, c x, (1/2)y, z; +(0, (1/2), 0) 4a; 4b 8e 2 × 4c 8e 2 × 4d 2 × 8e
[conventional setting]Pnna c, a, 2b z, x, (1/2)y; +(0, 0, (1/2))
[2] Pncn (52) a, 2b, c x, (1/2)y + (1/4), z; +(0, (1/2), 0) 8e 4a; 4b 2 × 4c 2 × 4d 8e 2 × 8e
[conventional setting]Pnna c, a, 2b z, x, (1/2)y + (1/4); +(0, 0, (1/2))
   Enlarged unit cell, isomorphic
[3] Pcca 3a, b, c (1/3)x, y, z; ±((1/3), 0, 0) 4a; 8f 4b; 8f 4c; 8f 4d; 8f 4e; 8f 3 × 8f
[p] Pcca pa, b, c (1/p)x, y, z; +((u/p), 0, 0) 4a; ((p - 1)/2) × 8f 4b; ((p - 1)/2) × 8f 4c; ((p - 1)/2) × 8f 4d; ((p - 1)/2) × 8f 4e; ((p - 1)/2) × 8f p × 8f
p = prime > 2; u = 1, . . ., p - 1
[2] Pcca a, 2b, c x, (1/2)y, z; +(0, (1/2), 0) 4a; 4b 8f 2 × 4c 4d; 4e 8f 2 × 8f
[2] Pcca a, 2b, c x, (1/2)y + (1/4), z; +(0, (1/2), 0) 8f 4a; 4b 2 × 4c 8f 4d; 4e 2 × 8f
[3] Pcca a, 3b, c x, (1/3)y, z; ±(0, (1/3), 0) 4a; 8f 4b; 8f 3 × 4c 4d; 8f 4e; 8f 3 × 8f
[p] Pcca a, pb, c x, (1/p)y, z; +(0, (u/p), 0) 4a; ((p - 1)/2) × 8f 4b; ((p - 1)/2) × 8f p × 4c 4d; ((p - 1)/2) × 8f 4e; ((p - 1)/2) × 8f p × 8f
p = prime > 2; u = 1, . . ., p - 1
[3] Pcca a, b, 3c x, y, (1/3)z; ±(0, 0, (1/3)) 4a; 8f 4b; 8f 4c; 8f 3 × 4d 3 × 4e 3 × 8f
[p] Pcca a, b, pc x, y, (1/p)z; +(0, 0, (u/p)) 4a; ((p - 1)/2) × 8f 4b; ((p - 1)/2) × 8f 4c; ((p - 1)/2) × 8f p × 4d p × 4e p × 8f
p = prime > 2; u = 1, . . ., p - 1


Nonconventional settings
        interchange letters and sequences in Hermann-Mauguin symbols, axes and coordinates:
Pbaa a→ b → c → a a→ b → c → a x→ y → z → x
Pbcb a← b ← c ← a a← b ← c ← a x← y ← z ← x
Pccb a<-> b a<-> -b x<-> -y
Pcaa a<-> c a<-> -c x<-> -z
Pbab b<-> c b<-> -c y<-> -z









































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