Crystal Lab › Prototype structures › Monoclinic
SiAs
Monoclinic · space group C12/m1 (No. 12) · Pearson mC24
Symmetry elements and Wyckoff positions (interactive)
SiAs in C12/m1
SettingUnit cell
- Lattice constants
- a = 15.980 Å, b = 3.668 Å, c = 9.529 Å; α = 90.00°, β = 106.00°, γ = 90.00°
- Cell volume
- 536.9 ų
- Atoms in the conventional cell
- 24 (As 12, Si 12)
- Formula units Z
- 12
- Pearson symbol
- mC24 — monoclinic, base-centred lattice, 24 atoms per conventional cell
- Symmetry operations
- 8 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| As1 | As | 4i | 4 | 0.3368 | 0.0000 | 0.8262 |
| As2 | As | 4i | 4 | 0.0369 | 0.0000 | 0.8239 |
| As3 | As | 4i | 4 | 0.6521 | 0.0000 | 0.5457 |
| Si4 | Si | 4i | 4 | 0.7387 | 0.0000 | 0.7924 |
| Si5 | Si | 4i | 4 | 0.6303 | 0.0000 | 0.9162 |
| Si6 | Si | 4i | 4 | 0.0661 | 0.0000 | 0.5884 |
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 24 atoms drawn above are these sites multiplied by all 8 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
AB_mC24_12_3i_3i-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol mC24, then the space-group number 12, then the Wyckoff letters occupied by each element in turn (As: 4i; As: 4i; As: 4i; Si: 4i; Si: 4i; Si: 4i). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
GaTe, GeAs <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB_mC24_12_3i_3i-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.
← CuAl · Space group C12/m1 (79 prototypes) · All prototypes · α-BiI →