Crystal Lab › Prototype structures › Orthorhombic
β'-AuCd (B19)
Orthorhombic · space group Pmma (No. 51) · Pearson oP4 · Strukturbericht B19
Symmetry elements and Wyckoff positions (interactive)
β'-AuCd (B19) in Pmma
SettingUnit cell
- Lattice constants
- a = 4.755 Å, b = 3.148 Å, c = 4.855 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 72.7 ų
- Atoms in the conventional cell
- 4 (Au 2, Cd 2)
- Formula units Z
- 2
- Pearson symbol
- oP4 — orthorhombic, primitive lattice, 4 atoms per conventional cell
- Symmetry operations
- 8 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Au1 | Au | 2e | 2 | 0.2500 | 0.0000 | 0.8125 |
| Cd2 | Cd | 2f | 2 | 0.2500 | 0.5000 | 0.3125 |
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 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
AB_oP4_51_e_f-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 51, then the Wyckoff letters occupied by each element in turn (Au: 2e; Cd: 2f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
AuTi (H.T.), CdMg, IrMo, IrW, MoPt (H.T.), MoRh, NbPt, NbRh, TiPb, TiPd, TiPt, VPt (L.T.) <!--beginning with an
Note: B19, \beta'-AuCd.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB_oP4_51_e_f-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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