Superconductivity up to 126 Kelvin in Interstitially Doped Ba2Can-1CunOx02(n-1)n-Ba

A new high-temperature superconducting compound system, Ba 2 Ca n – 1 Cu n O x 02( n –1) n –Ba interstitially doped with calcium or (Ca,Cu) has been identified to exhibit a transition temperature up to 126 kelvin, the highest for a superconductor without a volatile toxic element. 02( n –1) n –Ba has body-centered tetragonal symmetry and an unusual charge-reservoir block. The compounds offer interesting opportunities for high-temperature superconductivity science and technology.