Skip to content

Crystal Lab › Prototype structures › Cubic

α-AgI (B23)

Cubic · space group Im-3m (No. 229) · Pearson cI44 · Strukturbericht B23

Symmetry elements and Wyckoff positions (interactive)

α-AgI (B23) in Im-3m

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

Unit cell

Lattice constants
a = 5.034 Å, b = 5.034 Å, c = 5.034 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
127.6 ų
Atoms in the conventional cell
44 (I 2, Ag 42)
Formula units Z
2
Pearson symbol
cI44 — cubic, body-centred lattice, 44 atoms per conventional cell
Symmetry operations
96 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
I4I2a20.00000.00000.0000
Ag1Ag6b60.00000.50000.5000
Ag2Ag12d120.25000.00000.5000
Ag3Ag24h240.00000.37500.3750

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 44 atoms drawn above are these sites multiplied by all 96 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

A21B_cI44_229_bdh_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol cI44, then the space-group number 229, then the Wyckoff letters occupied by each element in turn (I: 2a; Ag: 6b; Ag: 12d; Ag: 24h). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

Ag₂S, Ag₂Se <!--beginning with an

Note: B23.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A21B_cI44_229_bdh_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.

 ·  Space group Im-3m (14 prototypes)  ·  All prototypes  ·  Sb₂Tl₇ (L2₂) →