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Crystal Lab › Prototype structures › Tetragonal

K₃CrO₈

Tetragonal · space group I-42m (No. 121) · Pearson tI24

Symmetry elements and Wyckoff positions (interactive)

K₃CrO₈ in I-42m

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

Unit cell

Lattice constants
a = 6.703 Å, b = 6.703 Å, c = 7.632 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
342.9 ų
Atoms in the conventional cell
24 (Cr 2, K 6, O 16)
Formula units Z
2
Pearson symbol
tI24 — tetragonal, body-centred lattice, 24 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Cr1Cr2a20.00000.00000.0000
K2K2b20.00000.00000.5000
K3K4d40.00000.50000.2500
O4O8i80.13550.13550.1788
O5O8i80.70790.70790.5082

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 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

AB3C8_tI24_121_a_bd_2i-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI24, then the space-group number 121, then the Wyckoff letters occupied by each element in turn (Cr: 2a; K: 2b; K: 4d; O: 8i; O: 8i). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

Zr₃GeO₈ <!--beginning with an

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB3C8_tI24_121_a_bd_2i-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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