Crystal Lab › Prototype structures › Hexagonal
Ce₂Ni₇
Hexagonal · space group P63/mmc (No. 194) · Pearson hP36
Symmetry elements and Wyckoff positions (interactive)
Ce₂Ni₇ in P63/mmc
SettingUnit cell
- Lattice constants
- a = 4.980 Å, b = 4.980 Å, c = 24.520 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 526.6 ų
- Atoms in the conventional cell
- 36 (Ni 28, Ce 8)
- Formula units Z
- 4
- Pearson symbol
- hP36 — hexagonal / trigonal, primitive lattice, 36 atoms per conventional cell
- Symmetry operations
- 24 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ni1 | Ni | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| Ni2 | Ni | 4e | 4 | 0.0000 | 0.0000 | 0.1670 |
| Ce3 | Ce | 4f | 4 | 0.3333 | 0.6667 | 0.5302 |
| Ce4 | Ce | 4f | 4 | 0.3333 | 0.6667 | 0.6747 |
| Ni5 | Ni | 4f | 4 | 0.3333 | 0.6667 | 0.1666 |
| Ni6 | Ni | 6h | 6 | 0.1649 | 0.3298 | 0.2500 |
| Ni7 | Ni | 12k | 12 | 0.8338 | 0.6676 | 0.9146 |
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 36 atoms drawn above are these sites multiplied by all 24 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
A2B7_hP36_194_2f_aefhk-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP36, then the space-group number 194, then the Wyckoff letters occupied by each element in turn (Ni: 2a; Ni: 4e; Ce: 4f; Ce: 4f; Ni: 4f; Ni: 6h; Ni: 12k). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Ce₂Co₇, Dy₂Ni₇, Er₂Ni₇, Eu₂Pt₇, Gd₂Co₇, Gd₂Ni₇, La₂Co₇, La₂Ir₇, La₂Ni₇, La₂Rh₇, Nd₂Co₇, Nd₂Ni₇, Pr₂Co₇, Pr₂Ni₇, Sc₂Ni₇, Sm₂Co₇, Sm₂Ni₇, Tb₂Ni₇, Th₂Co₇, Th₂Fe₇, Th₂Ni₇, Y₂Ni₇ <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B7_hP36_194_2f_aefhk-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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