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Crystal Lab › Prototype structures › Orthorhombic

NaAlCl₄

Orthorhombic · space group P212121 (No. 19) · Pearson oP24

Symmetry elements and Wyckoff positions (interactive)

NaAlCl₄ in P212121

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

Unit cell

Lattice constants
a = 9.886 Å, b = 6.167 Å, c = 10.322 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
629.3 ų
Atoms in the conventional cell
24 (Al 4, Cl 16, Na 4)
Formula units Z
4
Pearson symbol
oP24 — orthorhombic, primitive lattice, 24 atoms per conventional cell
Symmetry operations
4 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Al1Al4a40.51430.20710.9623
Cl2Cl4a40.68550.10960.8515
Cl3Cl4a40.33500.07340.8773
Cl4Cl4a40.52260.07460.1537
Cl5Cl4a40.50870.55280.9679
Na6Na4a40.71340.31120.3747

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 24 atoms drawn above are these sites multiplied by all 4 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

AB4C_oP24_19_a_4a_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP24, then the space-group number 19, then the Wyckoff letters occupied by each element in turn (Al: 4a; Cl: 4a; Cl: 4a; Cl: 4a; Cl: 4a; Na: 4a). 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 AB4C_oP24_19_a_4a_a-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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