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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

Setting
Loading the group…
x = 0.10, y = 0.17, z = 0.08

Unit 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

SiteElementWyckoffMultiplicityxyz
Ir1Ir8a80.00000.25000.3750
O2O16d160.00000.25000.4547
Sr4Sr16d160.00000.25000.5506
O3O16f160.20120.45120.1250

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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