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Crystal Lab › Prototype structures › Tetragonal

HgBa₂Ca₂Cu₃O₈ (Hg-1223)

Tetragonal · space group P4/mmm (No. 123) · Pearson tP16

Symmetry elements and Wyckoff positions (interactive)

HgBa₂Ca₂Cu₃O₈ (Hg-1223) in P4/mmm

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

Unit cell

Lattice constants
a = 3.846 Å, b = 3.846 Å, c = 15.773 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
233.3 ų
Atoms in the conventional cell
16 (Hg 1, Cu 3, O 8, Ba 2, Ca 2)
Formula units Z
1
Pearson symbol
tP16 — tetragonal, primitive lattice, 16 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Hg1Hg1a10.00000.00000.0000
Cu2Cu1b10.00000.00000.5000
O3O2e20.00000.50000.5000
Cu4Cu2g20.00000.00000.2988
O5O2g20.00000.00000.1246
Ba6Ba2h20.50000.50000.1735
Ca7Ca2h20.50000.50000.3973
O8O4i40.00000.50000.3009

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 16 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

A2B2C3DE8_tP16_123_h_h_bg_a_egi-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP16, then the space-group number 123, then the Wyckoff letters occupied by each element in turn (Hg: 1a; Cu: 1b; O: 2e; Cu: 2g; O: 2g; Ba: 2h; Ca: 2h; O: 4i). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: Hg-1223.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B2C3DE8_tP16_123_h_h_bg_a_egi-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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