Skip to content

Crystal Lab › Prototype structures › Trigonal

IrGe₄

Trigonal · space group P31 (No. 144) · Pearson hP15

Symmetry elements and Wyckoff positions (interactive)

IrGe₄ in P31

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

Unit cell

Lattice constants
a = 6.215 Å, b = 6.215 Å, c = 7.784 Å; α = 90.00°, β = 90.00°, γ = 120.00°
Cell volume
260.4 ų
Atoms in the conventional cell
15 (Ge 12, Ir 3)
Formula units Z
3
Pearson symbol
hP15 — hexagonal / trigonal, primitive lattice, 15 atoms per conventional cell
Symmetry operations
3 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Ge1Ge3a30.49040.21940.2268
Ge2Ge3a30.22260.48730.1142
Ge3Ge3a30.07750.00120.0000
Ge4Ge3a30.60970.00140.0018
Ir5Ir3a30.31780.00080.5062

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 15 atoms drawn above are these sites multiplied by all 3 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

A4B_hP15_144_4a_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP15, then the space-group number 144, then the Wyckoff letters occupied by each element in turn (Ge: 3a; Ge: 3a; Ge: 3a; Ge: 3a; Ir: 3a). 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 A4B_hP15_144_4a_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.

 ·  Space group P31 (3 prototypes)  ·  All prototypes  ·  RbNO₃ (IV) →