Crystal Lab › Prototype structures › Hexagonal
Mg₂Ni (C_{a})
Hexagonal · space group P6222 (No. 180) · Pearson hP18 · Strukturbericht Ca
Symmetry elements and Wyckoff positions (interactive)
Mg₂Ni (C_{a}) in P6222
SettingUnit cell
- Lattice constants
- a = 5.198 Å, b = 5.198 Å, c = 13.210 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 309.1 ų
- Atoms in the conventional cell
- 18 (Ni 6, Mg 12)
- Formula units Z
- 6
- Pearson symbol
- hP18 — hexagonal / trigonal, primitive lattice, 18 atoms per conventional cell
- Symmetry operations
- 12 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ni3 | Ni | 3a | 3 | 0.0000 | 0.0000 | 0.0000 |
| Ni4 | Ni | 3c | 3 | 0.5000 | 0.0000 | 0.0000 |
| Mg1 | Mg | 6f | 6 | 0.5000 | 0.0000 | 0.6149 |
| Mg2 | Mg | 6j | 6 | 0.1635 | 0.3270 | 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 18 atoms drawn above are these sites multiplied by all 12 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
A2B_hP18_180_fj_ac-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP18, then the space-group number 180, then the Wyckoff letters occupied by each element in turn (Ni: 3a; Ni: 3c; Mg: 6f; Mg: 6j). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
CuMg₄Ni, MoSn₂ <!--beginning with an
Note: C_{a}.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B_hP18_180_fj_ac-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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