Crystal Lab › Prototype structures › Tetragonal
ThCr₂Si₂
Tetragonal · space group I4/mmm (No. 139) · Pearson tI10
Symmetry elements and Wyckoff positions (interactive)
ThCr₂Si₂ in I4/mmm
SettingUnit cell
- Lattice constants
- a = 4.043 Å, b = 4.043 Å, c = 10.577 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 172.9 ų
- Atoms in the conventional cell
- 10 (Th 2, Cr 4, Si 4)
- Formula units Z
- 2
- Pearson symbol
- tI10 — tetragonal, body-centred lattice, 10 atoms per conventional cell
- Symmetry operations
- 32 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Th3 | Th | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| Cr1 | Cr | 4d | 4 | 0.0000 | 0.5000 | 0.2500 |
| Si2 | Si | 4e | 4 | 0.0000 | 0.0000 | 0.3740 |
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 10 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_tI10_139_d_e_a-003: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI10, then the space-group number 139, then the Wyckoff letters occupied by each element in turn (Th: 2a; Cr: 4d; Si: 4e). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
BaAl₂Ge₂, BaFe₂As₂, BaFe₂P₂, BaMg₂Si₂, BaMg₂Ge₂, BaMn₂Ge₂, BaNi₂As₂, BaNi₂Ge₂, BaRh₂B₂, CaAl₂Zn₂, CaAu₂Si₂, CaFe₂As₂, CaMn₂Ge₂, CaNi₂Ge₂, CaPd₂As₂, CeAl₂Ga₂, CeCu₂Si₂, CeMn₂Ge₂, CeRh₂Ge₂, CeRh₂Si₂, CeRu₂Si₂, CsCo₂As₂, CsCo₂P₂, CsFe₂As₂, CsFe₂P₂, CsIr₂As₂, CsIr₂P₂, CsRh₂As₂, CsRh₂P₂, CsRu₂As₂, CsRu₂P₂, DyCr₂Si₂, EuCo₂As₂, EuCo₂P₂, EuFe₂P₂, EuRh₂P₂, GdRu₂Ge₂, GdRu₂Si₂, GdRu₂Sn₂, KNi₂S₂, KNi₂Se₂, LaCo₂P₂, LaRu₂P₂, LuFe₂B₂, LuRu₂Si₂, PuCr₂Si₂, SrCo₂P₂, SrFe₂As₂, SrFe₂P₂, SrNi₂P₂, SrRh₂As₂, SrRh₂P₂, SrRu₂P₂, ThCr₂Si₂, ThCu₂Si₂, ThMn₂Ge₂, ThMn₂Si₂, ThNi₂Si₂, TlCu₂Se₂, UCr₂Si₂, URu₂Si₂, YFe₂Ge₂, YNi₂
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B2C_tI10_139_d_e_a-003 (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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