Crystal Lab › Prototype structures › Tetragonal
Gd₃Al₂
Tetragonal · space group P42nm (No. 102) · Pearson tP20
Symmetry elements and Wyckoff positions (interactive)
Gd₃Al₂ in P42nm
SettingUnit cell
- Lattice constants
- a = 8.344 Å, b = 8.344 Å, c = 7.656 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 533.0 ų
- Atoms in the conventional cell
- 20 (Gd 12, Al 8)
- 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 |
|---|---|---|---|---|---|---|
| Gd3 | Gd | 4b | 4 | 0.0000 | 0.5000 | 0.5000 |
| Al1 | Al | 4c | 4 | 0.3770 | 0.3770 | 0.0310 |
| Al2 | Al | 4c | 4 | 0.3960 | 0.3960 | 0.4390 |
| Gd4 | Gd | 4c | 4 | 0.1520 | 0.1520 | 0.2510 |
| Gd5 | Gd | 4c | 4 | 0.2050 | 0.2050 | 0.7250 |
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
A2B3_tP20_102_2c_b2c-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 102, then the Wyckoff letters occupied by each element in turn (Gd: 4b; Al: 4c; Al: 4c; Gd: 4c; Gd: 4c). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Dy₃Al₂, Er₃Al₂, Ho₃Al₂, Tb₃Al₂, Y₃Al₂, Zr₃Al₂ <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B3_tP20_102_2c_b2c-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.
· Space group P42nm (2 prototypes) · All prototypes · S₂ (S₄N₂) →