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Crystal Lab › Prototype structures › Tetragonal

SrTb₂Fe₂O₇

Tetragonal · space group P42/mnm (No. 136) · Pearson tP48

Symmetry elements and Wyckoff positions (interactive)

SrTb₂Fe₂O₇ in P42/mnm

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

Unit cell

Lattice constants
a = 5.506 Å, b = 5.506 Å, c = 19.659 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
596.1 ų
Atoms in the conventional cell
48 (O 28, Sr 4, Fe 8, Tb 8)
Formula units Z
4
Pearson symbol
tP48 — tetragonal, primitive lattice, 48 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
O2O4e40.00000.00000.6080
O3O4e40.00000.00000.9080
O4O4f40.78400.78400.0000
Sr7Sr4g40.23600.76400.0000
O5O8h80.00000.50000.6260
Fe1Fe8j80.24800.24800.9006
O6O8j80.20700.20700.7850
Tb8Tb8j80.27600.27600.6823

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 48 atoms drawn above are these sites multiplied by all 16 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

A2B7CD2_tP48_136_j_2efhj_g_j-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP48, then the space-group number 136, then the Wyckoff letters occupied by each element in turn (O: 4e; O: 4e; O: 4f; Sr: 4g; O: 8h; Fe: 8j; O: 8j; Tb: 8j). 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 A2B7CD2_tP48_136_j_2efhj_g_j-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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