Note 1 to entry: A perovskite-type structure has typical compositional and structural blocks of ABO₃, where A and B refer to metallic elements and O is oxygen.

Note 2 to entry A perovskite superconductor includes Ba (Pb_1-xBi_x) O₃ and (Ba_1-xM_x) BiO₃ (where M=K, Rb).

Note 3 to entry: This entry was numbered 815-11-06 in IEC 60050-815:2015.