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Crystal Lab › Prototype structures › Tetragonal

RbAlF₄ II AlF₄Rb

Tetragonal · space group P4/mbm (No. 127) · Pearson tP12

Symmetry elements and Wyckoff positions (interactive)

RbAlF₄ II in P4/mbm

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

Unit cell

Lattice constants
a = 5.123 Å, b = 5.123 Å, c = 6.282 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
164.8 ų
Atoms in the conventional cell
12 (Al 2, Rb 2, F 8)
Formula units Z
2
Pearson symbol
tP12 — tetragonal, primitive lattice, 12 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Al1Al2a20.00000.00000.0000
Rb4Rb2c20.00000.50000.5000
F2F4e40.00000.00000.2224
F3F4g40.21590.71590.0000

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 12 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

AB4C_tP12_127_a_eg_c-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP12, then the space-group number 127, then the Wyckoff letters occupied by each element in turn (Al: 2a; Rb: 2c; F: 4e; F: 4g). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: RbAlF₄ II.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB4C_tP12_127_a_eg_c-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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