Table 1875. I4/mcm (140) space group.
Name in the International Tables for Crystallography |
I4/mcm |
|
I |
|
139 |
|
4/mmm |
Crystal system |
Tetragonal |
|
4/mmm |
Asymm |
0 ≤ x ≤ 1/2 and 0 ≤ y ≤ 1/2 and 0 ≤ z ≤ 1/4 and y ≤ 1/2-x |
|
32 |
Extinction conditions |
k = 2n and l = 2n for 0 k l reflections (same as I-4c2 and I4cm). |
Symmetry (atomic coordinates) |
X, Y, Z;
-X, -Y, Z;
-Y, X, Z;
Y, -X, Z;
-X, Y, 1/2-Z;
X, -Y, 1/2-Z;
Y, X, 1/2-Z;
-Y, -X, 1/2-Z;
-X, -Y, -Z;
X, Y, -Z;
Y, -X, -Z;
-Y, X, -Z;
X, -Y, 1/2+Z;
-X, Y, 1/2+Z;
-Y, -X, 1/2+Z;
Y, X, 1/2+Z;
1/2+X, 1/2+Y, 1/2+Z;
1/2-X, 1/2-Y, 1/2+Z;
1/2-Y, 1/2+X, 1/2+Z;
1/2+Y, 1/2-X, 1/2+Z;
1/2-X, 1/2+Y, -Z;
1/2+X, 1/2-Y, -Z;
1/2+Y, 1/2+X, -Z;
1/2-Y, 1/2-X, -Z;
1/2-X, 1/2-Y, 1/2-Z;
1/2+X, 1/2+Y, 1/2-Z;
1/2+Y, 1/2-X, 1/2-Z;
1/2-Y, 1/2+X, 1/2-Z;
1/2+X, 1/2-Y, Z;
1/2-X, 1/2+Y, Z;
1/2-Y, 1/2-X, Z;
1/2+Y, 1/2+X, Z |
Other characteristics |
For distorted perovskite structures, the adjacent octahedra along the c-axes are rotated in antiphase manner. |
Crystal examples |
SrTiO3 (a = 5.513 Å and c = 7.807 Å):: Sr (4b): (0, 0.5, 0.25), Ti (4c): (0, 0, 0), O (4a): (0, 0, 0.25), and O (8h): (u, u+0.5, 0)
CaTiO3, CeAlO3, CeVO3, CaCsCl3, KMnF3, LaVO3, RbAgF3, SrTiO3, SrZrO3, La0.75Sm0.25VO3, SrMn0.5Sb0.5O3, SrMn0.5Sb0.5O3 |
|