Crystal Lab › Prototype structures › Orthorhombic
Base-Centered Orthorhombic La₂CuO₄ CuLa₂O₄
Orthorhombic · space group Cmce (No. 64) · Pearson oC28
Symmetry elements and Wyckoff positions (interactive)
Base-Centered Orthorhombic La₂CuO₄ in Cmce
SettingUnit cell
- Lattice constants
- a = 5.357 Å, b = 13.143 Å, c = 5.406 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 380.6 ų
- Atoms in the conventional cell
- 28 (Cu 4, O 16, La 8)
- Formula units Z
- 4
- Pearson symbol
- oC28 — orthorhombic, base-centred lattice, 28 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Cu1 | Cu | 4a | 4 | 0.0000 | 0.0000 | 0.0000 |
| O3 | O | 8e | 8 | 0.2500 | 0.0072 | 0.2500 |
| La2 | La | 8f | 8 | 0.0000 | 0.6385 | 0.9933 |
| O4 | O | 8f | 8 | 0.0000 | 0.8163 | 0.0341 |
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 28 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
AB2C4_oC28_64_a_f_ef-003: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oC28, then the space-group number 64, then the Wyckoff letters occupied by each element in turn (Cu: 4a; O: 8e; La: 8f; O: 8f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
La₂NiO₄, Nd₂CeO₄, Sc₂(La, Sr)O₄ <!--beginning with an
Note: BCO La₂CuO₄.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2C4_oC28_64_a_f_ef-003 (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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