Si₂N₂O

Unit cell

Lattice constants

a = 8.843 Å, b = 5.473 Å, c = 4.835 Å; α = 90.00°, β = 90.00°, γ = 90.00°

Cell volume

234.0 ų

Atoms in the conventional cell

20 (O 4, N 8, Si 8)

Formula units Z

4

Pearson symbol

oC20 — orthorhombic, base-centred lattice, 20 atoms per conventional cell

Symmetry operations

8 per cell

Crystallographic sites

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 20 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

A2BC2_oC20_36_b_a_b-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oC20, then the space-group number 36, then the Wyckoff letters occupied by each element in turn (O: 4a; N: 8b; Si: 8b). 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 A2BC2_oC20_36_b_a_b-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.