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Crystal Lab › Prototype structures › Hexagonal

Osumilite (KMg₂Al₃Si₁₂O₃₀)

Hexagonal · space group P6/mcc (No. 192) · Pearson hP96 · mineral: osumilite

Symmetry elements and Wyckoff positions (interactive)

Osumilite (KMg₂Al₃Si₁₂O₃₀) in P6/mcc

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

Unit cell

Lattice constants
a = 10.086 Å, b = 10.086 Å, c = 14.325 Å; α = 90.00°, β = 90.00°, γ = 120.00°
Cell volume
1262.0 ų
Atoms in the conventional cell
96 (K 2, Mg 4, Al 6, O 60, Si 24)
Formula units Z
2
Pearson symbol
hP96 — hexagonal / trigonal, primitive lattice, 96 atoms per conventional cell
Symmetry operations
24 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
K2K2a20.00000.00000.2500
Mg3Mg4c40.33330.66670.2500
Al1Al6f60.50000.00000.2500
O4O12l120.12290.40790.0000
O5O24m240.21660.28470.1320
O6O24m240.13980.49340.1790
Si7Si24m240.24820.35360.3921

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 96 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

A3BC2D30E12_hP96_192_f_a_c_l2m_m-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP96, then the space-group number 192, then the Wyckoff letters occupied by each element in turn (K: 2a; Mg: 4c; Al: 6f; O: 12l; O: 24m; O: 24m; Si: 24m). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: Osumilite.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A3BC2D30E12_hP96_192_f_a_c_l2m_m-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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