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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

Setting
Loading the group…
x = 0.10, y = 0.17, z = 0.08

Unit 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

SiteElementWyckoffMultiplicityxyz
Fe1Fe6c60.00000.00000.1441
Fe2Fe6c60.00000.00000.3507
O3O18f180.86100.32280.5272
O4O18f180.89070.41170.6318
O5O18f180.15890.46210.5769
O6O18f180.91940.14670.5992
S7S18f180.95710.33560.5840

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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