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Crystal Lab › Prototype structures › Tetragonal

0201 [(La,Ba)₂CuO₄] High-T_{c}

Tetragonal · space group I4/mmm (No. 139) · Pearson tI14

Symmetry elements and Wyckoff positions (interactive)

0201 [(La,Ba)₂CuO₄] High-T_{c} in I4/mmm

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

Unit cell

Lattice constants
a = 3.782 Å, b = 3.782 Å, c = 13.249 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
189.5 ų
Atoms in the conventional cell
14 (Cu 2, O 8, La 4)
Formula units Z
2
Pearson symbol
tI14 — tetragonal, body-centred lattice, 14 atoms per conventional cell
Symmetry operations
32 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Cu1Cu2a20.00000.00000.0000
O3O4c40.00000.50000.0000
La2La4e40.00000.00000.3608
O4O4e40.00000.00000.1824

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 14 atoms drawn above are these sites multiplied by all 32 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

AB2C4_tI14_139_a_e_ce-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI14, then the space-group number 139, then the Wyckoff letters occupied by each element in turn (Cu: 2a; O: 4c; La: 4e; O: 4e). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

Ba₂CuO_{3+delta} <!--beginning with an

Note: High-T_{c}.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2C4_tI14_139_a_e_ce-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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