Crystal Lab › Prototype structures › Trigonal
Proustite (Ag₃AsS₃)
Trigonal · space group R3c (No. 161) · Pearson hR14 · mineral: proustite
Symmetry elements and Wyckoff positions (interactive)
Proustite (Ag₃AsS₃) in R3c
SettingUnit cell
- Lattice constants
- a = 10.740 Å, b = 10.740 Å, c = 8.640 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 863.1 ų
- Atoms in the conventional cell
- 42 (As 6, Ag 18, S 18)
- Formula units Z
- 6
- Pearson symbol
- hR14 — hexagonal / trigonal, rhombohedral lattice, 14 atoms per conventional cell
- Symmetry operations
- 18 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| As2 | As | 6a | 6 | 0.0000 | 0.0000 | 0.0000 |
| Ag1 | Ag | 18b | 18 | 0.7187 | 0.0873 | 0.5683 |
| S3 | S | 18b | 18 | 0.8750 | 0.7800 | 0.3850 |
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 42 atoms drawn above are these sites multiplied by all 18 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
A3BC3_hR14_161_b_a_b-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hR14, then the space-group number 161, then the Wyckoff letters occupied by each element in turn (As: 6a; Ag: 18b; S: 18b). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Ag₃AsSe₃, Ag₃SbS₃ (pyrargyrite) <!--beginning with an
Note: Proustite.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A3BC3_hR14_161_b_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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