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Crystal Lab › Prototype structures › Trigonal

BaNi₂As₂O₈

Trigonal · space group R-3 (No. 148) · Pearson hR13

Symmetry elements and Wyckoff positions (interactive)

BaNi₂As₂O₈ in R-3

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

Unit cell

Lattice constants
a = 4.936 Å, b = 4.936 Å, c = 23.610 Å; α = 90.00°, β = 90.00°, γ = 120.00°
Cell volume
498.2 ų
Atoms in the conventional cell
39 (Ba 3, As 6, Ni 6, O 24)
Formula units Z
3
Pearson symbol
hR13 — hexagonal / trigonal, rhombohedral lattice, 13 atoms per conventional cell
Symmetry operations
18 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Ba2Ba3a30.00000.00000.0000
As1As6c60.00000.00000.4270
Ni3Ni6c60.00000.00000.1670
O4O6c60.00000.00000.3550
O5O18f180.00000.67200.1130

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 39 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

A2BC2D8_hR13_148_c_a_c_cf-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hR13, then the space-group number 148, then the Wyckoff letters occupied by each element in turn (Ba: 3a; As: 6c; Ni: 6c; O: 6c; O: 18f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

BaCo₂As₂O₈, BaCo₂P₂O₈, BaCo₂Sb₂O₈, BaMg₂As₂O₈, BaNi₂P₂O₈, BaNi₂V₂O₈ <!--beginning with an

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2BC2D8_hR13_148_c_a_c_cf-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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