Crystal Lab › Prototype structures › Tetragonal
Maucherite (Ni₁₁As₈)
Tetragonal · space group P41212 (No. 92) · Pearson tP76 · mineral: maucherite
Symmetry elements and Wyckoff positions (interactive)
Maucherite (Ni₁₁As₈) in P41212
SettingUnit cell
- Lattice constants
- a = 6.872 Å, b = 6.872 Å, c = 21.821 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 1030.6 ų
- Atoms in the conventional cell
- 76 (As 32, Ni 44)
- Formula units Z
- 4
- Pearson symbol
- tP76 — tetragonal, primitive lattice, 76 atoms per conventional cell
- Symmetry operations
- 8 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| As1 | As | 4a | 4 | 0.1200 | 0.1200 | 0.0000 |
| As2 | As | 4a | 4 | 0.6350 | 0.6350 | 0.0000 |
| Ni6 | Ni | 4a | 4 | 0.3750 | 0.3750 | 0.0000 |
| As3 | As | 8b | 8 | 0.6350 | 0.1290 | 0.0004 |
| As4 | As | 8b | 8 | 0.8770 | 0.3820 | 0.1250 |
| As5 | As | 8b | 8 | 0.1210 | 0.8690 | 0.1289 |
| Ni10 | Ni | 8b | 8 | 0.3720 | 0.6830 | 0.0805 |
| Ni11 | Ni | 8b | 8 | 0.8710 | 0.6900 | 0.0770 |
| Ni7 | Ni | 8b | 8 | 0.1250 | 0.3730 | 0.2686 |
| Ni8 | Ni | 8b | 8 | 0.1200 | 0.5690 | 0.1734 |
| Ni9 | Ni | 8b | 8 | 0.6080 | 0.5620 | 0.1710 |
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 76 atoms drawn above are these sites multiplied by all 8 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
A8B11_tP76_92_2a3b_a5b-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP76, then the space-group number 92, then the Wyckoff letters occupied by each element in turn (As: 4a; As: 4a; Ni: 4a; As: 8b; As: 8b; As: 8b; Ni: 8b; Ni: 8b; Ni: 8b; Ni: 8b; Ni: 8b). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: Maucherite.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A8B11_tP76_92_2a3b_a5b-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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