Crystal Lab › Prototype structures › Hexagonal
Na₃As (D0₁₈)
Hexagonal · space group P63/mmc (No. 194) · Pearson hP8 · Strukturbericht D018
Symmetry elements and Wyckoff positions (interactive)
Na₃As (D0₁₈) in P63/mmc
SettingUnit cell
- Lattice constants
- a = 5.088 Å, b = 5.088 Å, c = 8.982 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 201.4 ų
- Atoms in the conventional cell
- 8 (Na 6, As 2)
- Formula units Z
- 2
- Pearson symbol
- hP8 — hexagonal / trigonal, primitive lattice, 8 atoms per conventional cell
- Symmetry operations
- 24 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Na2 | Na | 2b | 2 | 0.0000 | 1.0000 | 0.2500 |
| As1 | As | 2c | 2 | 0.3333 | 0.6667 | 0.2500 |
| Na3 | Na | 4f | 4 | 0.3333 | 0.6667 | 0.9170 |
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 8 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
AB3_hP8_194_c_bf-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP8, then the space-group number 194, then the Wyckoff letters occupied by each element in turn (Na: 2b; As: 2c; Na: 4f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
K₃As, K₃P, K₃Sb, Li₃As, Mg₃Au, Mg₃Ir, Mg₃Pd, Mg₃Pt, Mg₃Si, Na₃Bi, Na₃P, Na₃Sb, Rb₃As, Rb₃Bi, Rb₃Sb, K₂NaSb <!--beginning with an
Note: D0₁₈.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB3_hP8_194_c_bf-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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