Crystal Lab › Prototype structures › Orthorhombic
Parkerite (Ni₃Bi₂S₄)
Orthorhombic · space group Pmma (No. 51) · Pearson oP8 · mineral: parkerite
Symmetry elements and Wyckoff positions (interactive)
Parkerite (Ni₃Bi₂S₄) in Pmma
SettingUnit cell
- Lattice constants
- a = 5.545 Å, b = 4.052 Å, c = 5.731 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 128.8 ų
- Atoms in the conventional cell
- 8 (Ni 4, Bi 2, S 2)
- Formula units Z
- 2
- Pearson symbol
- oP8 — orthorhombic, primitive lattice, 8 atoms per conventional cell
- Symmetry operations
- 8 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ni2 | Ni | 2b | 2 | 0.0000 | 0.5000 | 0.0000 |
| Bi1 | Bi | 2e | 2 | 0.2500 | 0.0000 | 0.7423 |
| Ni3 | Ni | 2e | 2 | 0.2500 | 0.0000 | 0.2040 |
| S4 | S | 2f | 2 | 0.2500 | 0.5000 | 0.2560 |
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 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
AB2C_oP8_51_e_be_f-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP8, then the space-group number 51, then the Wyckoff letters occupied by each element in turn (Ni: 2b; Bi: 2e; Ni: 2e; S: 2f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Ni₃(Bi, Pb)₂S₄ <!--beginning with an
Note: Parkerite.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2C_oP8_51_e_be_f-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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