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Crystal Lab › Prototype structures › Orthorhombic

β-SrRh₂As₂ As₂Rh₂Sr

Orthorhombic · space group Fmmm (No. 69) · Pearson oF20

Symmetry elements and Wyckoff positions (interactive)

β-SrRh₂As₂ in Fmmm

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

Unit cell

Lattice constants
a = 11.144 Å, b = 5.744 Å, c = 6.115 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
391.4 ų
Atoms in the conventional cell
20 (Sr 4, Rh 8, As 8)
Formula units Z
4
Pearson symbol
oF20 — orthorhombic, face-centred lattice, 20 atoms per conventional cell
Symmetry operations
32 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Sr3Sr4a40.00000.00000.0000
Rh2Rh8f80.25000.25000.2500
As1As8g80.64100.00000.0000

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 20 atoms drawn above are these sites multiplied by all 32 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

A2B2C_oF20_69_g_f_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oF20, then the space-group number 69, then the Wyckoff letters occupied by each element in turn (Sr: 4a; Rh: 8f; As: 8g). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

EuRh₂As₂ <!--beginning with an

Note: \beta-SrRh₂As₂.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B2C_oF20_69_g_f_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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