Crystal Lab › Prototype structures › Tetragonal
α-MgAgSb AgMgSb
Tetragonal · space group I-4c2 (No. 120) · Pearson tI48
Symmetry elements and Wyckoff positions (interactive)
α-MgAgSb in I-4c2
SettingUnit cell
- Lattice constants
- a = 9.176 Å, b = 9.176 Å, c = 12.696 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 1069.0 ų
- Atoms in the conventional cell
- 48 (Ag 16, Mg 16, Sb 16)
- Formula units Z
- 16
- Pearson symbol
- tI48 — tetragonal, body-centred lattice, 48 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ag1 | Ag | 4a | 4 | 0.0000 | 0.0000 | 0.2500 |
| Ag2 | Ag | 4b | 4 | 0.0000 | 0.0000 | 0.0000 |
| Ag3 | Ag | 8e | 8 | 0.2247 | 0.2247 | 0.2500 |
| Mg4 | Mg | 16i | 16 | -0.0360 | 0.2960 | 0.0960 |
| Sb5 | Sb | 16i | 16 | 0.2363 | 0.4749 | 0.1203 |
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 48 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
ABC_tI48_120_abe_i_i-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI48, then the space-group number 120, then the Wyckoff letters occupied by each element in turn (Ag: 4a; Ag: 4b; Ag: 8e; Mg: 16i; Sb: 16i). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: α-MgAgSb.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry ABC_tI48_120_abe_i_i-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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