Structure of A2BX4 Ruddlesden-Popper hybrid halide perovskites

Here B is Sn or Pb, X is Br or I, A is a molecule with cationic tail (e.g. -NH3) fitting A-site and large body disrupting 3D packing. It is a stack of weakly interacting 2D layers, each layer is a square lattice of BX6 corner-sharing octahedra with A cations. In notations of p4/mmm layer group, B occupies (1a)=(0,0,0) site, X occupies (2c)=(1/2,0,0) and (2d)=(0,0,z) sites, and the cationic tail of A sits at (2e)=(1/2,1/2,z) site. Interlayer packing is governed mainly by steric effects with the most common displacement of (1/2,1/2,z) in p4/mmm notations.

Notations

• See notations common for all CMSOS projects here
• Filename notations
• Dataname notations
• Considered cations

Results for A2SnI4

• CIF files
• Unit cell parameters and symmetry
• Geometry of the first BX6 octahedron
• Geometry of octahedra and coordination of halides (average and min/max)
• Geometry of the first cation and symmetry deviation of other cations

© 2026 Andriy Zhugayevych