Crystal Lab › Prototype structures › Tetragonal
Na₃Hg₂
Tetragonal · space group P42/mnm (No. 136) · Pearson tP20
Symmetry elements and Wyckoff positions (interactive)
Na₃Hg₂ in P42/mnm
SettingUnit cell
- Lattice constants
- a = 8.520 Å, b = 8.520 Å, c = 7.800 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 566.2 ų
- Atoms in the conventional cell
- 20 (Na 12, Hg 8)
- Formula units Z
- 4
- Pearson symbol
- tP20 — tetragonal, primitive lattice, 20 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Na2 | Na | 4c | 4 | 0.0000 | 0.5000 | 0.0000 |
| Na3 | Na | 4f | 4 | 0.3680 | 0.3680 | 0.0000 |
| Na4 | Na | 4g | 4 | 0.2100 | 0.7900 | 0.0000 |
| Hg1 | Hg | 8j | 8 | 0.1250 | 0.1250 | 0.1900 |
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 20 atoms drawn above are these sites multiplied by all 16 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
A2B3_tP20_136_j_cfg-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP20, then the space-group number 136, then the Wyckoff letters occupied by each element in turn (Na: 4c; Na: 4f; Na: 4g; Hg: 8j). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Al₂Zr₃ <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B3_tP20_136_j_cfg-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.
← Rh₆Mn₅Bi₁₈ · Space group P42/mnm (18 prototypes) · All prototypes · Zr₃Al₂ →