Crystal Lab › Prototype structures › Tetragonal
CaCuO₂
Tetragonal · space group P4/mmm (No. 123) · Pearson tP4
Symmetry elements and Wyckoff positions (interactive)
CaCuO₂ in P4/mmm
SettingUnit cell
- Lattice constants
- a = 3.861 Å, b = 3.861 Å, c = 3.200 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 47.7 ų
- Atoms in the conventional cell
- 4 (Ca 1, Cu 1, O 2)
- Formula units Z
- 1
- Pearson symbol
- tP4 — tetragonal, primitive lattice, 4 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ca1 | Ca | 1a | 1 | 0.0000 | 0.0000 | 0.0000 |
| Cu2 | Cu | 1d | 1 | 0.5000 | 0.5000 | 0.5000 |
| O3 | O | 2e | 2 | 0.0000 | 0.5000 | 0.5000 |
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 4 atoms drawn above are these sites multiplied by all 16 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
ABC2_tP4_123_a_d_e-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP4, then the space-group number 123, then the Wyckoff letters occupied by each element in turn (Ca: 1a; Cu: 1d; O: 2e). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
(Ba, Sr)CuO₂, (Sr, La)CuO₂, (Sr, Ca)CuO₂, LaNiO₂, NdNiO₂, CsNiF₂, KNiF₂, LiNiF₂, NaNiF₂, RbNiF₂ <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry ABC2_tP4_123_a_d_e-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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