Crystal Lab › Prototype structures › Tetragonal
Fe₈N (D2_{g})
Tetragonal · space group I4/mmm (No. 139) · Pearson tI18 · Strukturbericht D2g
Symmetry elements and Wyckoff positions (interactive)
Fe₈N (D2_{g}) in I4/mmm
SettingUnit cell
- Lattice constants
- a = 5.714 Å, b = 5.714 Å, c = 6.288 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 205.3 ų
- Atoms in the conventional cell
- 18 (N 2, Fe 16)
- Formula units Z
- 2
- Pearson symbol
- tI18 — tetragonal, body-centred lattice, 18 atoms per conventional cell
- Symmetry operations
- 32 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| N4 | N | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| Fe1 | Fe | 4d | 4 | 0.0000 | 0.5000 | 0.2500 |
| Fe2 | Fe | 4e | 4 | 0.0000 | 0.0000 | 0.2922 |
| Fe3 | Fe | 8h | 8 | 0.2443 | 0.2443 | 0.0000 |
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 18 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
A8B_tI18_139_deh_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI18, then the space-group number 139, then the Wyckoff letters occupied by each element in turn (N: 2a; Fe: 4d; Fe: 4e; Fe: 8h). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: D2_{g}.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A8B_tI18_139_deh_a-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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