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Crystal Lab › Prototype structures › Trigonal

Sc₇Cl₁₂

Trigonal · space group R-3 (No. 148) · Pearson hR19

Symmetry elements and Wyckoff positions (interactive)

Sc₇Cl₁₂ in R-3

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

Unit cell

Lattice constants
a = 12.959 Å, b = 12.959 Å, c = 8.825 Å; α = 90.00°, β = 90.00°, γ = 120.00°
Cell volume
1283.5 ų
Atoms in the conventional cell
57 (Sc 21, Cl 36)
Formula units Z
3
Pearson symbol
hR19 — hexagonal / trigonal, rhombohedral lattice, 19 atoms per conventional cell
Symmetry operations
18 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Sc3Sc3a30.00000.00000.0000
Cl1Cl18f180.31170.22990.5048
Cl2Cl18f180.13120.18210.8354
Sc4Sc18f180.16060.04350.6474

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 57 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

A12B7_hR19_148_2f_af-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hR19, then the space-group number 148, then the Wyckoff letters occupied by each element in turn (Sc: 3a; Cl: 18f; Cl: 18f; Sc: 18f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A12B7_hR19_148_2f_af-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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