Crystal Lab › Prototype structures › Tetragonal
Cu₄Pd
Tetragonal · space group P42/m (No. 84) · Pearson tP20
Symmetry elements and Wyckoff positions (interactive)
Cu₄Pd in P42/m
SettingUnit cell
- Lattice constants
- a = 5.826 Å, b = 5.826 Å, c = 7.328 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 248.7 ų
- Atoms in the conventional cell
- 20 (Cu 16, Pd 4)
- Formula units Z
- 4
- Pearson symbol
- tP20 — tetragonal, primitive lattice, 20 atoms per conventional cell
- Symmetry operations
- 8 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Cu1 | Cu | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| Cu2 | Cu | 2f | 2 | 0.5000 | 0.5000 | 0.2500 |
| Cu3 | Cu | 4j | 4 | 0.2000 | 0.6000 | 0.0000 |
| Pd5 | Pd | 4j | 4 | 0.4000 | 0.2000 | 0.0000 |
| Cu4 | Cu | 8k | 8 | 0.1000 | 0.3000 | 0.2500 |
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 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
A4B_tP20_84_afjk_j-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 84, then the Wyckoff letters occupied by each element in turn (Cu: 2a; Cu: 2f; Cu: 4j; Pd: 4j; Cu: 8k). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A4B_tP20_84_afjk_j-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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