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Crystal Lab › Prototype structures › Hexagonal

Sr₂Be₂B₂O₇

Hexagonal · space group P-6c2 (No. 188) · Pearson hP26

Symmetry elements and Wyckoff positions (interactive)

Sr₂Be₂B₂O₇ in P-6c2

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

Unit cell

Lattice constants
a = 4.683 Å, b = 4.683 Å, c = 15.311 Å; α = 90.00°, β = 90.00°, γ = 120.00°
Cell volume
290.8 ų
Atoms in the conventional cell
26 (Sr 4, O 14, Be 4, B 4)
Formula units Z
2
Pearson symbol
hP26 — hexagonal / trigonal, primitive lattice, 26 atoms per conventional cell
Symmetry operations
12 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Sr5Sr2a21.00000.00000.0000
Sr6Sr2b21.00000.00000.2500
O3O2c20.33330.66670.0000
Be2Be4h40.33330.66670.1066
B1B4i40.66670.33330.1279
O4O12l120.62890.02210.1382

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 26 atoms drawn above are these sites multiplied by all 12 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

A2B2C7D2_hP26_188_i_h_cl_ab-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP26, then the space-group number 188, then the Wyckoff letters occupied by each element in turn (Sr: 2a; Sr: 2b; O: 2c; Be: 4h; B: 4i; O: 12l). 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 A2B2C7D2_hP26_188_i_h_cl_ab-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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