Crystal Lab › Prototype structures › Cubic
β-Alum [Al(NH₃CH₃)₂(SO₄)₂ cdot 12H₂O, H4₁₄]
Cubic · space group Pa-3 (No. 205) · Pearson cP252 · Strukturbericht H414 · mineral: beta-alum
Symmetry elements and Wyckoff positions (interactive)
β-Alum [Al(NH₃CH₃)₂(SO₄)₂ cdot 12H₂O, H4₁₄] in Pa-3
SettingUnit cell
- Lattice constants
- a = 12.314 Å, b = 12.314 Å, c = 12.314 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 1867.2 ų
- Atoms in the conventional cell
- 252 (Al 4, C 8, N 8, O 80, S 8, H 144)
- Formula units Z
- 4
- Pearson symbol
- cP252 — cubic, primitive lattice, 252 atoms per conventional cell
- Symmetry operations
- 24 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Al1 | Al | 4a | 4 | 0.0000 | 0.0000 | 0.0000 |
| C2 | C | 8c | 8 | 0.4501 | 0.4501 | 0.4501 |
| N9 | N | 8c | 8 | 0.5156 | 0.5156 | 0.5156 |
| O10 | O | 8c | 8 | 0.2341 | 0.2341 | 0.2341 |
| S14 | S | 8c | 8 | 0.3022 | 0.3022 | 0.3022 |
| H3 | H | 24d | 24 | 0.3851 | 0.5072 | 0.4134 |
| H4 | H | 24d | 24 | 0.0837 | 0.5363 | 0.0275 |
| H5 | H | 24d | 24 | 0.5423 | 0.2018 | 0.4728 |
| H6 | H | 24d | 24 | 0.4132 | 0.1846 | 0.4502 |
| H7 | H | 24d | 24 | 0.2143 | 0.4941 | 0.1944 |
| H8 | H | 24d | 24 | 0.2148 | 0.6103 | 0.1697 |
| O11 | O | 24d | 24 | 0.6911 | 0.7530 | 0.0914 |
| O12 | O | 24d | 24 | 0.8521 | 0.9810 | 0.0185 |
| O13 | O | 24d | 24 | 0.0419 | 0.1373 | 0.2975 |
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 252 atoms drawn above are these sites multiplied by all 24 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
AB2C36D2E20F2_cP252_205_a_c_6d_c_c3d_c-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol cP252, then the space-group number 205, then the Wyckoff letters occupied by each element in turn (Al: 4a; C: 8c; N: 8c; O: 8c; S: 8c; H: 24d; H: 24d; H: 24d; H: 24d; H: 24d; H: 24d; O: 24d; O: 24d; O: 24d). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
AlCs(SO₄)₂ cdot 12H₂O <!--beginning with an
Note: \beta-Alum.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2C36D2E20F2_cP252_205_a_c_6d_c_c3d_c-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.
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