Crystal Lab › Prototype structures › Trigonal
Cinnabar (HgS, B9)
Trigonal · space group P3221 (No. 154) · Pearson hP6 · Strukturbericht B9 · mineral: cinnabar
Symmetry elements and Wyckoff positions (interactive)
Cinnabar (HgS, B9) in P3221
SettingUnit cell
- Lattice constants
- a = 4.145 Å, b = 4.145 Å, c = 9.496 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 141.3 ų
- Atoms in the conventional cell
- 6 (Hg 3, S 3)
- Formula units Z
- 3
- Pearson symbol
- hP6 — hexagonal / trigonal, primitive lattice, 6 atoms per conventional cell
- Symmetry operations
- 6 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Hg1 | Hg | 3a | 3 | 0.7198 | 0.0000 | 0.6667 |
| S2 | S | 3b | 3 | 0.4889 | 0.0000 | 0.1667 |
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 6 atoms drawn above are these sites multiplied by all 6 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_hP6_154_a_b-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP6, then the space-group number 154, then the Wyckoff letters occupied by each element in turn (Hg: 3a; S: 3b). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
HgO <!--beginning with an
Note: B9, Cinnabar.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB_hP6_154_a_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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