Crystal Lab › Prototype structures › Hexagonal
Moissanite-6H SiC (B6)
Hexagonal · space group P63mc (No. 186) · Pearson hP12 · Strukturbericht B6 · mineral: moissanite
Symmetry elements and Wyckoff positions (interactive)
Moissanite-6H SiC (B6) in P63mc
SettingUnit cell
- Lattice constants
- a = 3.081 Å, b = 3.081 Å, c = 15.120 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 124.3 ų
- Atoms in the conventional cell
- 12 (C 6, Si 6)
- Formula units Z
- 6
- Pearson symbol
- hP12 — hexagonal / trigonal, primitive lattice, 12 atoms per conventional cell
- Symmetry operations
- 12 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| C1 | C | 2a | 2 | 0.0000 | 0.0000 | 0.1254 |
| Si4 | Si | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| C2 | C | 2b | 2 | 0.3333 | 0.6667 | 0.2922 |
| C3 | C | 2b | 2 | 0.3333 | 0.6667 | 0.9585 |
| Si5 | Si | 2b | 2 | 0.3333 | 0.6667 | 0.1668 |
| Si6 | Si | 2b | 2 | 0.3333 | 0.6667 | 0.8335 |
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 12 atoms drawn above are these sites multiplied by all 12 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_hP12_186_a2b_a2b-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP12, then the space-group number 186, then the Wyckoff letters occupied by each element in turn (C: 2a; Si: 2a; C: 2b; C: 2b; Si: 2b; Si: 2b). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: B6, 6H-Moissanite.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB_hP12_186_a2b_a2b-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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