Crystal Lab › Prototype structures › Hexagonal
MgNi₂ Hexagonal Laves (C36)
Hexagonal · space group P63/mmc (No. 194) · Pearson hP24 · Strukturbericht C36
Symmetry elements and Wyckoff positions (interactive)
MgNi₂ Hexagonal Laves (C36) in P63/mmc
SettingUnit cell
- Lattice constants
- a = 4.824 Å, b = 4.824 Å, c = 15.826 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 318.9 ų
- Atoms in the conventional cell
- 24 (Mg 8, Ni 16)
- Formula units Z
- 8
- Pearson symbol
- hP24 — hexagonal / trigonal, primitive lattice, 24 atoms per conventional cell
- Symmetry operations
- 24 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Mg1 | Mg | 4e | 4 | 0.0000 | 0.0000 | 0.0940 |
| Mg2 | Mg | 4f | 4 | 0.3333 | 0.6667 | 0.8442 |
| Ni3 | Ni | 4f | 4 | 0.3333 | 0.6667 | 0.1251 |
| Ni4 | Ni | 6g | 6 | 0.5000 | 0.0000 | 0.0000 |
| Ni5 | Ni | 6h | 6 | 0.1643 | 0.3286 | 0.2500 |
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 24 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
AB2_hP24_194_ef_fgh-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP24, then the space-group number 194, then the Wyckoff letters occupied by each element in turn (Mg: 4e; Mg: 4f; Ni: 4f; Ni: 6g; Ni: 6h). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
CdCu₂, HfCr₂, HfFe₂, HfMo₂ (HT), NbCo₂, NbZn₂, ScFe₂, ThMg₂ (LT), β-TiCo₂, UPt₂ <!--beginning with an
Note: C36, Hexagonal Laves.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2_hP24_194_ef_fgh-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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