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Crystal Lab › Prototype structures › Trigonal

Cu₂Ta₄O₁₁

Trigonal · space group R-3c (No. 167) · Pearson hR36

Symmetry elements and Wyckoff positions (interactive)

Cu₂Ta₄O₁₁ in R-3c

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

Unit cell

Lattice constants
a = 6.219 Å, b = 6.219 Å, c = 37.107 Å; α = 90.00°, β = 90.00°, γ = 120.00°
Cell volume
1242.9 ų
Atoms in the conventional cell
108 (Ta 24, O 66, Cu 18)
Formula units Z
6
Pearson symbol
hR36 — hexagonal / trigonal, rhombohedral lattice, 36 atoms per conventional cell
Symmetry operations
36 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Ta5Ta6b60.00000.00000.0000
O2O12c120.00000.00000.4069
Cu1Cu18d180.50000.00000.0000
O3O18e180.24570.00000.2500
Ta6Ta18e180.63740.00000.2500
O4O36f360.37030.94370.6978

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 108 atoms drawn above are these sites multiplied by all 36 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

A3B11C4_hR36_167_d_cef_be-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hR36, then the space-group number 167, then the Wyckoff letters occupied by each element in turn (Ta: 6b; O: 12c; Cu: 18d; O: 18e; Ta: 18e; O: 36f). 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 A3B11C4_hR36_167_d_cef_be-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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