Crystal Lab › Prototype structures › Orthorhombic
β-ThI₃ I₃Th
Orthorhombic · space group Cccm (No. 66) · Pearson oC64
Symmetry elements and Wyckoff positions (interactive)
β-ThI₃ in Cccm
SettingUnit cell
- Lattice constants
- a = 20.297 Å, b = 8.735 Å, c = 14.661 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 2599.3 ų
- Atoms in the conventional cell
- 64 (Th 16, I 48)
- Formula units Z
- 16
- Pearson symbol
- oC64 — orthorhombic, base-centred lattice, 64 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Th5 | Th | 4a | 4 | 0.0000 | 0.0000 | 0.2500 |
| Th6 | Th | 4c | 4 | 0.0000 | 0.0000 | 0.0000 |
| I1 | I | 8k | 8 | 0.2500 | 0.2500 | 0.1826 |
| I2 | I | 8l | 8 | 0.6994 | 0.0318 | 0.0000 |
| Th7 | Th | 8l | 8 | 0.6716 | 0.6730 | 0.0000 |
| I3 | I | 16m | 16 | 0.9510 | 0.7106 | 0.1302 |
| I4 | I | 16m | 16 | 0.8773 | 0.8867 | 0.3708 |
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 64 atoms drawn above are these sites multiplied by all 16 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
A3B_oC64_66_kl2m_acl-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oC64, then the space-group number 66, then the Wyckoff letters occupied by each element in turn (Th: 4a; Th: 4c; I: 8k; I: 8l; Th: 8l; I: 16m; I: 16m). 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 A3B_oC64_66_kl2m_acl-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.
← H₃S (60 GPa) · Space group Cccm (6 prototypes) · All prototypes · γ-Li₂IrO₃ — IrLi₂O₃ →