Crystal Lab › Prototype structures › Orthorhombic
Dyscrasite (Ag_{3.15}Sb_{0.85})
Orthorhombic · space group Pmm2 (No. 25) · Pearson oP4 · mineral: dyscrasite
Symmetry elements and Wyckoff positions (interactive)
Dyscrasite (Ag_{3.15}Sb_{0.85}) in Pmm2
SettingUnit cell
- Lattice constants
- a = 3.008 Å, b = 4.828 Å, c = 5.214 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 75.7 ų
- Atoms in the conventional cell
- 4 (Ag 3, Sb 1)
- Formula units Z
- 1
- Pearson symbol
- oP4 — orthorhombic, primitive lattice, 4 atoms per conventional cell
- Symmetry operations
- 4 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ag1 | Ag | 1a | 1 | 0.0000 | 0.0000 | 0.0000 |
| Ag2 | Ag | 1b | 1 | 0.0000 | 0.5000 | 0.3398 |
| Ag3 | Ag | 1c | 1 | 0.5000 | 0.0000 | 0.4879 |
| Sb4 | Sb | 1d | 1 | 0.5000 | 0.5000 | 0.8150 |
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 4 atoms drawn above are these sites multiplied by all 4 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
A3B_oP4_25_abc_d-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP4, then the space-group number 25, then the Wyckoff letters occupied by each element in turn (Ag: 1a; Ag: 1b; Ag: 1c; Sb: 1d). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: Dyscrasite.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A3B_oP4_25_abc_d-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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