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Shandite (Ni₃Pb₂S₂)

Trigonal · space group R-3m (No. 166) · Pearson hR7 · mineral: shandite

Symmetry elements and Wyckoff positions (interactive)

Shandite (Ni₃Pb₂S₂) in R-3m

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

Unit cell

Lattice constants
a = 5.595 Å, b = 5.595 Å, c = 13.626 Å; α = 90.00°, β = 90.00°, γ = 120.00°
Cell volume
369.4 ų
Atoms in the conventional cell
21 (Pb 6, S 6, Ni 9)
Formula units Z
3
Pearson symbol
hR7 — hexagonal / trigonal, rhombohedral lattice, 7 atoms per conventional cell
Symmetry operations
36 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Pb2Pb3a30.00000.00000.0000
Pb3Pb3b30.00000.00000.5000
S4S6c60.00000.00000.2750
Ni1Ni9d90.50000.00000.5000

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 21 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

A3B2C2_hR7_166_d_ab_c-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hR7, then the space-group number 166, then the Wyckoff letters occupied by each element in turn (Pb: 3a; Pb: 3b; S: 6c; Ni: 9d). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

Co₃In₂S₂, Co₃Sn₂S₂, Ni₃In₂S₂, Ni₃Sn₂S₂, Ni₃Tl₂S₂, O₃K₂Sn₂, Pd₃Bi₂S₂, Pd₃Pb₂S₂, Pt₃Pb₂S₂, Rh₃Pb₂S₂, Rh₃Tl₂S₂ <!--beginning with an

Note: Shandite.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A3B2C2_hR7_166_d_ab_c-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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