Crystal Lab › Prototype structures › Tetragonal
Sr₂IrO₄
Tetragonal · space group I41/acd (No. 142) · Pearson tI56
Symmetry elements and Wyckoff positions (interactive)
Sr₂IrO₄ in I41/acd
SettingUnit cell
- Lattice constants
- a = 5.498 Å, b = 5.498 Å, c = 25.798 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 779.8 ų
- Atoms in the conventional cell
- 56 (Ir 8, O 32, Sr 16)
- Formula units Z
- 8
- Pearson symbol
- tI56 — tetragonal, body-centred lattice, 56 atoms per conventional cell
- Symmetry operations
- 32 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ir1 | Ir | 8a | 8 | 0.0000 | 0.2500 | 0.3750 |
| O2 | O | 16d | 16 | 0.0000 | 0.2500 | 0.4547 |
| Sr4 | Sr | 16d | 16 | 0.0000 | 0.2500 | 0.5506 |
| O3 | O | 16f | 16 | 0.2012 | 0.4512 | 0.1250 |
The multiplicity and the Wyckoff letter say how many copies of the site the group makes in one cell and on which kind of symmetry element the site sits; the 56 atoms drawn above are these sites multiplied by all 32 operations. Press Wyckoff under Colour to see the sites, and tick a symmetry element on the left to see which atoms lie on it.
How to read the label
AB4C2_tI56_142_a_df_d-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI56, then the space-group number 142, then the Wyckoff letters occupied by each element in turn (Ir: 8a; O: 16d; Sr: 16d; O: 16f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Ca₂CrO₄, Ca₂MnO₄, Sr₂HfO₄, Sr₂RhO₄ <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB4C2_tI56_142_a_df_d-001 (M. J. Mehl et al., Comput. Mater. Sci. 136, S1 (2017); D. Hicks et al., ibid. 161, S1 (2019) and 199, 110450 (2021); S. Eckert et al., ibid. 240, 112988 (2024)). Symmetry elements, Wyckoff assignment and the diagram are computed on this page from the group operations.
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