Crystal Lab › Prototype structures › Orthorhombic
Ca₄Al₆O₁₆S
Orthorhombic · space group Pcc2 (No. 27) · Pearson oP108
Symmetry elements and Wyckoff positions (interactive)
Ca₄Al₆O₁₆S in Pcc2
SettingUnit cell
- Lattice constants
- a = 13.039 Å, b = 13.041 Å, c = 9.169 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 1559.2 ų
- Atoms in the conventional cell
- 108 (Al 24, Ca 16, O 64, S 4)
- Formula units Z
- 4
- Pearson symbol
- oP108 — orthorhombic, primitive lattice, 108 atoms per conventional cell
- Symmetry operations
- 4 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Al1 | Al | 2a | 2 | 0.0000 | 0.0000 | 0.2050 |
| Al3 | Al | 2b | 2 | 0.0000 | 0.5000 | 0.2500 |
| Al2 | Al | 2c | 2 | 0.5000 | 0.0000 | 0.2000 |
| Al4 | Al | 2d | 2 | 0.5000 | 0.5000 | 0.2300 |
| Al5 | Al | 4e | 4 | 0.8790 | 0.6270 | 0.9960 |
| Al6 | Al | 4e | 4 | 0.3750 | 0.1220 | 0.9490 |
| Al7 | Al | 4e | 4 | 0.3710 | 0.3690 | 0.9800 |
| Al8 | Al | 4e | 4 | 0.1240 | 0.1220 | 0.9600 |
| Ca10 | Ca | 4e | 4 | 0.0740 | 0.2370 | 0.2860 |
| Ca11 | Ca | 4e | 4 | 0.4880 | 0.2570 | 0.2540 |
| Ca12 | Ca | 4e | 4 | 0.7470 | 0.4830 | 0.2280 |
| Ca9 | Ca | 4e | 4 | 0.7490 | 0.0580 | 0.1490 |
| O13 | O | 4e | 4 | 0.6830 | 0.7290 | 0.6120 |
| O14 | O | 4e | 4 | 0.8160 | 0.8380 | 0.4600 |
| O15 | O | 4e | 4 | 0.6640 | 0.7700 | 0.3790 |
| O16 | O | 4e | 4 | 0.7990 | 0.6510 | 0.4170 |
| O17 | O | 4e | 4 | 0.7540 | 0.4000 | 0.4380 |
| O18 | O | 4e | 4 | 0.5910 | 0.5670 | 0.1400 |
| O19 | O | 4e | 4 | 0.8950 | 0.5550 | 0.1550 |
| O20 | O | 4e | 4 | 0.4100 | 0.7550 | 0.5040 |
| O21 | O | 4e | 4 | 0.5570 | 0.5960 | 0.8260 |
| O22 | O | 4e | 4 | 0.5540 | 0.9070 | 0.8020 |
| O23 | O | 4e | 4 | 0.0980 | 0.7570 | 0.5360 |
| O24 | O | 4e | 4 | 0.9660 | 0.9010 | 0.8240 |
| O25 | O | 4e | 4 | 0.9670 | 0.6080 | 0.8540 |
| O26 | O | 4e | 4 | 0.7530 | 0.1030 | 0.3910 |
| O27 | O | 4e | 4 | 0.8850 | 0.9530 | 0.1250 |
| O28 | O | 4e | 4 | 0.6110 | 0.9480 | 0.1100 |
| S29 | S | 4e | 4 | 0.7513 | 0.2537 | 0.9822 |
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 108 atoms drawn above are these sites multiplied by all 4 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
A6B4C16D_oP108_27_abcd4e_4e_16e_e-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP108, then the space-group number 27, then the Wyckoff letters occupied by each element in turn (Al: 2a; Al: 2b; Al: 2c; Al: 2d; Al: 4e; Al: 4e; Al: 4e; Al: 4e; Ca: 4e; Ca: 4e; Ca: 4e; Ca: 4e; O: 4e; O: 4e; O: 4e; O: 4e; O: 4e; O: 4e; O: 4e; O: 4e; O: 4e; O: 4e; O: 4e; O: 4e; O: 4e; O: 4e; O: 4e; O: 4e; S: 4e). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Sr₄Al₆O₁₆S <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A6B4C16D_oP108_27_abcd4e_4e_16e_e-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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