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Crystal Lab › Prototype structures › Trigonal

Ba₃SrTa₂O₉

Trigonal · space group P-3m1 (No. 164) · Pearson hP15

Symmetry elements and Wyckoff positions (interactive)

Ba₃SrTa₂O₉ in P-3m1

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

Unit cell

Lattice constants
a = 5.950 Å, b = 5.950 Å, c = 7.470 Å; α = 90.00°, β = 90.00°, γ = 120.00°
Cell volume
229.0 ų
Atoms in the conventional cell
15 (Ba 3, Sr 1, Ta 2, O 9)
Formula units Z
1
Pearson symbol
hP15 — hexagonal / trigonal, primitive lattice, 15 atoms per conventional cell
Symmetry operations
12 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Ba1Ba1a10.00000.00000.0000
Sr5Sr1b10.00000.00000.5000
Ba2Ba2d20.33330.66670.6667
Ta6Ta2d20.33330.66670.1667
O3O3e30.50000.00000.0000
O4O6i60.16670.83330.3333

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 12 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

A3B9CD2_hP15_164_ad_ei_b_d-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP15, then the space-group number 164, then the Wyckoff letters occupied by each element in turn (Ba: 1a; Sr: 1b; Ba: 2d; Ta: 2d; O: 3e; O: 6i). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

Ba₃CoNb₂O₉ <!--beginning with an

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A3B9CD2_hP15_164_ad_ei_b_d-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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