Crystal Lab › Prototype structures › Monoclinic
EuFeAs₂
Monoclinic · space group P121/m1 (No. 11) · Pearson mP8
Symmetry elements and Wyckoff positions (interactive)
EuFeAs₂ in P121/m1
SettingUnit cell
- Lattice constants
- a = 3.982 Å, b = 3.899 Å, c = 10.666 Å; α = 90.00°, β = 90.24°, γ = 90.00°
- Cell volume
- 165.6 ų
- Atoms in the conventional cell
- 8 (As 4, Eu 2, Fe 2)
- Formula units Z
- 2
- Pearson symbol
- mP8 — monoclinic, primitive lattice, 8 atoms per conventional cell
- Symmetry operations
- 4 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| As1 | As | 2e | 2 | 0.7496 | 0.2500 | 0.3666 |
| As2 | As | 2e | 2 | 0.2498 | 0.2500 | 0.0035 |
| Eu3 | Eu | 2e | 2 | 0.7540 | 0.2500 | 0.7716 |
| Fe4 | Fe | 2e | 2 | 0.2500 | 0.2500 | 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 8 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
A2BC_mP8_11_2e_e_e-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol mP8, then the space-group number 11, then the Wyckoff letters occupied by each element in turn (As: 2e; As: 2e; Eu: 2e; Fe: 2e). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2BC_mP8_11_2e_e_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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