**2.1 Structures**

Perovskite materials generally contain a cubic unit cell with the general formula ABX3. Cation A, which is larger than cation B, is in the center of the unit cell. The B cations are in every corner of the unit cell; Cation B also serves as the center of an octahedron with an X anion surrounding cation B, corner-sharing between each cation B. As shown in **Figure 1(b)**, the full picture of cation A is surrounded by eight octahedra, each of which contains a cationic center B and anions X. In this orientation, the cubic structure of the perovskite has 6-fold the coordination number for cation A and 12-fold the coordination number for cation B. It should be noted that the ionic radii are quite crucial in maintaining a stable cubic unit cell.
