Crystal Lab › Prototype structures › Trigonal
Mikasaite (Rhombohedral Fe₂(SO₄)₃)
Trigonal · space group R-3 (No. 148) · Pearson hR34 · mineral: mikasaite
Symmetry elements and Wyckoff positions (interactive)
Mikasaite (Rhombohedral Fe₂(SO₄)₃) in R-3
SettingUnit cell
- Lattice constants
- a = 8.236 Å, b = 8.236 Å, c = 22.179 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 1302.9 ų
- Atoms in the conventional cell
- 102 (Fe 12, O 72, S 18)
- Formula units Z
- 6
- Pearson symbol
- hR34 — hexagonal / trigonal, rhombohedral lattice, 34 atoms per conventional cell
- Symmetry operations
- 18 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Fe1 | Fe | 6c | 6 | 0.0000 | 0.0000 | 0.1441 |
| Fe2 | Fe | 6c | 6 | 0.0000 | 0.0000 | 0.3507 |
| O3 | O | 18f | 18 | 0.8610 | 0.3228 | 0.5272 |
| O4 | O | 18f | 18 | 0.8907 | 0.4117 | 0.6318 |
| O5 | O | 18f | 18 | 0.1589 | 0.4621 | 0.5769 |
| O6 | O | 18f | 18 | 0.9194 | 0.1467 | 0.5992 |
| S7 | S | 18f | 18 | 0.9571 | 0.3356 | 0.5840 |
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 102 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
A2B12C3_hR34_148_2c_4f_f-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hR34, then the space-group number 148, then the Wyckoff letters occupied by each element in turn (Fe: 6c; Fe: 6c; O: 18f; O: 18f; O: 18f; O: 18f; S: 18f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Al₂(SO₄)₃ <!--beginning with an
Note: Mikasaite.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B12C3_hR34_148_2c_4f_f-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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