Crystal Lab › Prototype structures › Trigonal
ErNi₃Al₉
Trigonal · space group R32 (No. 155) · Pearson hR26
Symmetry elements and Wyckoff positions (interactive)
ErNi₃Al₉ in R32
SettingUnit cell
- Lattice constants
- a = 7.272 Å, b = 7.272 Å, c = 27.346 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 1252.2 ų
- Atoms in the conventional cell
- 78 (Al 54, Er 6, Ni 18)
- Formula units Z
- 6
- Pearson symbol
- hR26 — hexagonal / trigonal, rhombohedral lattice, 26 atoms per conventional cell
- Symmetry operations
- 18 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Al1 | Al | 6c | 6 | 0.0000 | 0.0000 | 0.5521 |
| Al2 | Al | 6c | 6 | 0.0000 | 0.0000 | 0.7818 |
| Al3 | Al | 6c | 6 | 0.0000 | 0.0000 | 0.8871 |
| Er7 | Er | 6c | 6 | 0.0000 | 0.0000 | 0.6669 |
| Al5 | Al | 9d | 9 | 0.7903 | 0.0000 | 0.0000 |
| Al4 | Al | 9e | 9 | 0.6667 | 0.0000 | 0.5000 |
| Al6 | Al | 18f | 18 | 0.3311 | 0.9995 | 0.9330 |
| Ni8 | Ni | 18f | 18 | 0.6606 | 0.0002 | 0.9185 |
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 78 atoms drawn above are these sites multiplied by all 18 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
A9BC3_hR26_155_3cdef_c_f-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hR26, then the space-group number 155, then the Wyckoff letters occupied by each element in turn (Al: 6c; Al: 6c; Al: 6c; Er: 6c; Al: 9d; Al: 9e; Al: 18f; Ni: 18f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
DyNi₃Al₉, ErNi₃Al₉, GdNi₃Al₉, YNi₃Al₉, YbNi₃Al₉, YbNi₃Ga₉ <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A9BC3_hR26_155_3cdef_c_f-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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