Crystal Lab › Prototype structures › Monoclinic
Base-Centered Monoclinic La₂CuO₄ CuLa₂O₄
Monoclinic · space group C1m1 (No. 8) · Pearson mC28
Symmetry elements and Wyckoff positions (interactive)
Base-Centered Monoclinic La₂CuO₄ in C1m1
SettingUnit cell
- Lattice constants
- a = 13.143 Å, b = 5.357 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, La 8, O 16)
- Formula units Z
- 4
- Pearson symbol
- mC28 — monoclinic, base-centred lattice, 28 atoms per conventional cell
- Symmetry operations
- 4 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Cu1 | Cu | 2a | 2 | 0.0016 | 0.0000 | 0.0010 |
| Cu2 | Cu | 2a | 2 | 0.4984 | 0.0000 | 0.4997 |
| La3 | La | 2a | 2 | 0.6385 | 0.0000 | 0.9933 |
| La4 | La | 2a | 2 | 0.3615 | 0.0000 | 0.0067 |
| La5 | La | 2a | 2 | 0.1385 | 0.0000 | 0.5067 |
| La6 | La | 2a | 2 | 0.8615 | 0.0000 | 0.4933 |
| O10 | O | 2a | 2 | 0.3164 | 0.0000 | 0.5300 |
| O7 | O | 2a | 2 | 0.8164 | 0.0000 | 0.0300 |
| O8 | O | 2a | 2 | 0.1837 | 0.0000 | 0.9620 |
| O9 | O | 2a | 2 | 0.6836 | 0.0000 | 0.5380 |
| O11 | O | 4b | 4 | 0.0070 | 0.7500 | 0.2497 |
| O12 | O | 4b | 4 | 0.4925 | 0.2500 | 0.7496 |
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 4 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_mC28_8_2a_4a_4a2b-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol mC28, then the space-group number 8, then the Wyckoff letters occupied by each element in turn (Cu: 2a; Cu: 2a; La: 2a; La: 2a; La: 2a; La: 2a; O: 2a; O: 2a; O: 2a; O: 2a; O: 4b; O: 4b). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: BCM La₂CuO₄.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2C4_mC28_8_2a_4a_4a2b-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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