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α-AgI (B23)
Cubic · space group Im-3m (No. 229) · Pearson cI44 · Strukturbericht B23
Symmetry elements and Wyckoff positions (interactive)
α-AgI (B23) in Im-3m
SettingUnit cell
- Lattice constants
- a = 5.034 Å, b = 5.034 Å, c = 5.034 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 127.6 ų
- Atoms in the conventional cell
- 44 (I 2, Ag 42)
- Formula units Z
- 2
- Pearson symbol
- cI44 — cubic, body-centred lattice, 44 atoms per conventional cell
- Symmetry operations
- 96 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| I4 | I | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| Ag1 | Ag | 6b | 6 | 0.0000 | 0.5000 | 0.5000 |
| Ag2 | Ag | 12d | 12 | 0.2500 | 0.0000 | 0.5000 |
| Ag3 | Ag | 24h | 24 | 0.0000 | 0.3750 | 0.3750 |
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 44 atoms drawn above are these sites multiplied by all 96 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
A21B_cI44_229_bdh_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol cI44, then the space-group number 229, then the Wyckoff letters occupied by each element in turn (I: 2a; Ag: 6b; Ag: 12d; Ag: 24h). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Ag₂S, Ag₂Se <!--beginning with an
Note: B23.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A21B_cI44_229_bdh_a-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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