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Crystal Lab › Prototype structures › Tetragonal

CeCo₄B₄

Tetragonal · space group P42/nmc (No. 137) · Pearson tP18

Symmetry elements and Wyckoff positions (interactive)

CeCo₄B₄ in P42/nmc

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

Unit cell

Lattice constants
a = 5.059 Å, b = 5.059 Å, c = 7.063 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
180.8 ų
Atoms in the conventional cell
18 (Ce 2, B 8, Co 8)
Formula units Z
2
Pearson symbol
tP18 — tetragonal, primitive lattice, 18 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Ce2Ce2a20.75000.25000.7500
B1B8g80.25000.08000.6000
Co3Co8g80.25000.50300.8840

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 18 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

A4BC4_tP18_137_g_a_g-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP18, then the space-group number 137, then the Wyckoff letters occupied by each element in turn (Ce: 2a; B: 8g; Co: 8g). 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 A4BC4_tP18_137_g_a_g-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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