Crystal Lab › Prototype structures › Hexagonal
Nickeline (NiAs, B8₁)
Hexagonal · space group P63/mmc (No. 194) · Pearson hP4 · Strukturbericht B81 · mineral: nickeline
Symmetry elements and Wyckoff positions (interactive)
Nickeline (NiAs, B8₁) in P63/mmc
SettingUnit cell
- Lattice constants
- a = 3.619 Å, b = 3.619 Å, c = 5.044 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 57.2 ų
- Atoms in the conventional cell
- 4 (Ni 2, As 2)
- Formula units Z
- 2
- Pearson symbol
- hP4 — hexagonal / trigonal, primitive lattice, 4 atoms per conventional cell
- Symmetry operations
- 24 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ni2 | Ni | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| As1 | As | 2c | 2 | 0.3333 | 0.6667 | 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 4 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
AB_hP4_194_c_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP4, then the space-group number 194, then the Wyckoff letters occupied by each element in turn (Ni: 2a; As: 2c). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
AuSn, CoAs, β-CoS, CoSb, CoSe, CoTe, CrH, β-CrSb, CrSe, CuSn, FeS, α-FeSe, α''-FeSe, IrPb, IrS, IrSb, IrSn, IrTe, MgPo, MnAs, MnBi (L.T.), MnSb, MnTe (L.T.), NbS_{1+x}, NiBi, δ-NiS, NiSb, NiSe (H.T.), NiSn, NiTe, PdSb, PdTe, PtB, PtBi, PtPb, PtSb, PtSn, RhSe, RhSn, RhTe, ScSe, ThBi, β-TiAs, TiS, TiSb, TiSc, VP, VS, VSb, VSe, VTe, ZrTe <!--beginning with an
Note: B8₁, Nickeline.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB_hP4_194_c_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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