Crystal Lab › Prototype structures › Trigonal
Herbertsmithite (Cu₃Zn(OH)₆Cl₂)
Trigonal · space group R-3m (No. 166) · Pearson hR18 · mineral: herbertsmithite
Symmetry elements and Wyckoff positions (interactive)
Herbertsmithite (Cu₃Zn(OH)₆Cl₂) in R-3m
SettingUnit cell
- Lattice constants
- a = 6.834 Å, b = 6.834 Å, c = 14.075 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 569.3 ų
- Atoms in the conventional cell
- 54 (Zn 3, Cl 6, Cu 9, H 18, O 18)
- Formula units Z
- 3
- Pearson symbol
- hR18 — hexagonal / trigonal, rhombohedral lattice, 18 atoms per conventional cell
- Symmetry operations
- 36 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Zn5 | Zn | 3a | 3 | 0.0000 | 0.0000 | 0.0000 |
| Cl1 | Cl | 6c | 6 | 0.0000 | 0.0000 | 0.6943 |
| Cu2 | Cu | 9d | 9 | 0.5000 | 0.0000 | 0.5000 |
| H3 | H | 18h | 18 | 0.1380 | 0.8620 | 0.5862 |
| O4 | O | 18h | 18 | 0.2056 | 0.7944 | 0.5612 |
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 54 atoms drawn above are these sites multiplied by all 36 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
A2B3C6D6E_hR18_166_c_d_h_h_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hR18, then the space-group number 166, then the Wyckoff letters occupied by each element in turn (Zn: 3a; Cl: 6c; Cu: 9d; H: 18h; O: 18h). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Cu₃Ni(OH)₆Cl₂ (gillardite), Cu₃Mg_{x}(OH)₆Cl₂, Cu₃M(OH)₆Cl₂ (leverettite), Mg₃Mn_{x}(OH)₆Cl₂ <!--beginning with an
Note: Herbertsmithite.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B3C6D6E_hR18_166_c_d_h_h_a-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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