Crystal Lab › Prototype structures › Orthorhombic
High-Pressure oP8 Sodium Na
Orthorhombic · space group Pnma (No. 62) · Pearson oP8
Symmetry elements and Wyckoff positions (interactive)
High-Pressure oP8 Sodium in Pnma
SettingUnit cell
- Lattice constants
- a = 4.765 Å, b = 3.020 Å, c = 5.251 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 75.6 ų
- Atoms in the conventional cell
- 8 (Na 8)
- Formula units Z
- 8
- 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 |
|---|---|---|---|---|---|---|
| Na1 | Na | 4c | 4 | 0.0150 | 0.2500 | 0.1800 |
| Na2 | Na | 4c | 4 | 0.1640 | 0.2500 | 0.5860 |
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
A_oP8_62_2c-002: 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 62, then the Wyckoff letters occupied by each element in turn (Na: 4c; Na: 4c). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: HP.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A_oP8_62_2c-002 (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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