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Crystal Lab › Prototype structures › Trigonal

γ-Ag₃SI (Low-Temperature)

Trigonal · space group R3 (No. 146) · Pearson hR5

Symmetry elements and Wyckoff positions (interactive)

γ-Ag₃SI (Low-Temperature) in R3

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

Unit cell

Lattice constants
a = 6.886 Å, b = 6.886 Å, c = 8.434 Å; α = 90.00°, β = 90.00°, γ = 120.00°
Cell volume
346.3 ų
Atoms in the conventional cell
15 (I 3, S 3, Ag 9)
Formula units Z
3
Pearson symbol
hR5 — hexagonal / trigonal, rhombohedral lattice, 5 atoms per conventional cell
Symmetry operations
9 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
I2I3a30.00000.00000.4700
S3S3a30.00000.00000.0000
Ag1Ag9b90.55000.59200.4480

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 15 atoms drawn above are these sites multiplied by all 9 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

A3BC_hR5_146_b_a_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hR5, then the space-group number 146, then the Wyckoff letters occupied by each element in turn (I: 3a; S: 3a; Ag: 9b). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

CsGeCl₃ <!--beginning with an

Note: \gamma-Ag₃SI.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A3BC_hR5_146_b_a_a-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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