Abstract
It has been verified that Bi2Sr2CaCu2O x does not remain as an 80-K superconductor upon quenching. The resistivity zero of the low-T c Bi compound exceeds 90 K. We emphasize that Bi2Sr2CaCu2O x is equivalent to YBa2Cu3O7-δ as far as T c is concerned. The characteristic combination of two CuO2 layers may be responsible for the specification of T c.