Symmetry elements and Wyckoff positions (interactive)
Ca₇Ge in Fm-3m
SettingUnit cell
- Lattice constants
- a = 9.450 Å, b = 9.450 Å, c = 9.450 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 843.9 ų
- Atoms in the conventional cell
- 32 (Ca 28, Ge 4)
- Formula units Z
- 4
- Pearson symbol
- cF32 — cubic, face-centred lattice, 32 atoms per conventional cell
- Symmetry operations
- 192 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ca1 | Ca | 4a | 4 | 0.0000 | 0.0000 | 0.0000 |
| Ge3 | Ge | 4b | 4 | 0.5000 | 0.5000 | 0.5000 |
| Ca2 | Ca | 24d | 24 | 0.0000 | 0.2500 | 0.2500 |
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 32 atoms drawn above are these sites multiplied by all 192 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
A7B_cF32_225_ad_b-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol cF32, then the space-group number 225, then the Wyckoff letters occupied by each element in turn (Ca: 4a; Ge: 4b; Ca: 24d). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
CuPt₇, DyPd₇, LiPd₇, LiPt₇, SbPt₇, MoZn₇ <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A7B_cF32_225_ad_b-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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