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Crystal Lab › Prototype structures › Hexagonal

Zr₄Al₃

Hexagonal · space group P6/mmm (No. 191) · Pearson hP7

Symmetry elements and Wyckoff positions (interactive)

Zr₄Al₃ in P6/mmm

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

Unit cell

Lattice constants
a = 5.433 Å, b = 5.433 Å, c = 5.390 Å; α = 90.00°, β = 90.00°, γ = 120.00°
Cell volume
137.8 ų
Atoms in the conventional cell
7 (Zr 4, Al 3)
Formula units Z
1
Pearson symbol
hP7 — hexagonal / trigonal, primitive lattice, 7 atoms per conventional cell
Symmetry operations
24 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Zr2Zr2d20.33330.66670.5000
Zr3Zr2e20.00000.00000.2500
Al1Al3f30.50000.00000.0000

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 7 atoms drawn above are these sites multiplied by all 24 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

A3B4_hP7_191_f_de-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP7, then the space-group number 191, then the Wyckoff letters occupied by each element in turn (Zr: 2d; Zr: 2e; Al: 3f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

Hf₄Al₃ <!--beginning with an

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A3B4_hP7_191_f_de-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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