Crystal Lab › Prototype structures › Tetragonal
C (T12 Group IV)
Tetragonal · space group P42/ncm (No. 138) · Pearson tP12
Symmetry elements and Wyckoff positions (interactive)
C (T12 Group IV) in P42/ncm
SettingUnit cell
- Lattice constants
- a = 3.388 Å, b = 3.388 Å, c = 6.011 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 69.0 ų
- Atoms in the conventional cell
- 12 (C 12)
- Formula units Z
- 12
- Pearson symbol
- tP12 — tetragonal, primitive lattice, 12 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| C1 | C | 4b | 4 | 0.7500 | 0.2500 | 0.7500 |
| C2 | C | 8i | 8 | 0.0860 | 0.0860 | 0.1070 |
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 12 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
A_tP12_138_bi-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP12, then the space-group number 138, then the Wyckoff letters occupied by each element in turn (C: 4b; C: 8i). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Ge, Si <!--beginning with an
Note: T12, Theory.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A_tP12_138_bi-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.
← Tetragonal La₂NiO₄ · Space group P42/ncm (3 prototypes) · All prototypes · Cl (A18) Structure ( Obsolete ): A_tP16_138_j-001 →