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Crystal Lab › Prototype structures › Trigonal

ErNi₃Al₉

Trigonal · space group R32 (No. 155) · Pearson hR26

Symmetry elements and Wyckoff positions (interactive)

ErNi₃Al₉ in R32

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

Unit cell

Lattice constants
a = 7.272 Å, b = 7.272 Å, c = 27.346 Å; α = 90.00°, β = 90.00°, γ = 120.00°
Cell volume
1252.2 ų
Atoms in the conventional cell
78 (Al 54, Er 6, Ni 18)
Formula units Z
6
Pearson symbol
hR26 — hexagonal / trigonal, rhombohedral lattice, 26 atoms per conventional cell
Symmetry operations
18 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Al1Al6c60.00000.00000.5521
Al2Al6c60.00000.00000.7818
Al3Al6c60.00000.00000.8871
Er7Er6c60.00000.00000.6669
Al5Al9d90.79030.00000.0000
Al4Al9e90.66670.00000.5000
Al6Al18f180.33110.99950.9330
Ni8Ni18f180.66060.00020.9185

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 78 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

A9BC3_hR26_155_3cdef_c_f-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hR26, then the space-group number 155, then the Wyckoff letters occupied by each element in turn (Al: 6c; Al: 6c; Al: 6c; Er: 6c; Al: 9d; Al: 9e; Al: 18f; Ni: 18f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

DyNi₃Al₉, ErNi₃Al₉, GdNi₃Al₉, YNi₃Al₉, YbNi₃Al₉, YbNi₃Ga₉ <!--beginning with an

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A9BC3_hR26_155_3cdef_c_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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