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Crystal Lab › Prototype structures › Tetragonal

HgBa₂CaCu₂O_{6+delta} Ba₂CaCu₂HgO₇

Tetragonal · space group P4/mmm (No. 123) · Pearson tP13

Symmetry elements and Wyckoff positions (interactive)

HgBa₂CaCu₂O_{6+delta} in P4/mmm

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

Unit cell

Lattice constants
a = 3.853 Å, b = 3.853 Å, c = 12.652 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
187.8 ų
Atoms in the conventional cell
13 (O 7, Ca 1, Hg 1, Ba 2, Cu 2)
Formula units Z
1
Pearson symbol
tP13 — tetragonal, primitive lattice, 13 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
O5O1a10.00000.00000.0000
Ca2Ca1b10.00000.00000.5000
Hg4Hg1c10.50000.50000.0000
Ba1Ba2g20.00000.00000.2216
Cu3Cu2h20.50000.50000.3771
O6O2h20.50000.50000.1565
O7O4i40.00000.50000.3772

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 13 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

A2BC2DE7_tP13_123_g_b_h_c_ahi-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP13, then the space-group number 123, then the Wyckoff letters occupied by each element in turn (O: 1a; Ca: 1b; Hg: 1c; Ba: 2g; Cu: 2h; O: 2h; O: 4i). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

TlBa₂CaCu₂O_{6+delta} <!--beginning with an

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2BC2DE7_tP13_123_g_b_h_c_ahi-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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