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Chemistry · Glossary

What is Perovskite structure?

Also known as: tolerance factor

Definition 23.8 University Chemistry — Year 3 · Chapter 23 — Inorganic Materials and Nanomaterials

The perovskite structure of an oxide ABO3\mathrm{ABO_3} has the small B cations at the centres of corner-sharing BO6\mathrm{BO_6} octahedra and the large A cations in the twelve-coordinate cavities between them; in the ideal cubic cell, B is at the centre, O at the face centres, A at the corners. The tolerance factor measures how well the ions fit:

t=rA+rO2 (rB+rO).t = \frac{r_A + r_O}{\sqrt2\,(r_B + r_O)}.
The cubic perovskite cell ABO_3: a B cation (grey) at the centre of an octahedron of six oxide ions at the face centres (green edges), the A cations at the corners. Each corner A ion is shared by eight cells and each oxygen by two: one A, one B and three O per cell.
The cubic perovskite cell ABO3\mathrm{ABO_3}: a B cation (grey) at the centre of an octahedron of six oxide ions at the face centres (green edges), the A cations at the corners. Each corner A ion is shared by eight cells and each oxygen by two: one A, one B and three O per cell.
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