Chemistry of Oxide Superconductors

Superconductivity has been observed in La sub 2-x (Sr, Ba, Ca) sub x CuO sub 4 at temperatures near 40K. This paper presents data on other substitutions in this phase and on a number of other phases with the K sub 2 NiF sub 4 structure. Data is also presented on a number of other metallic oxide systems that hold promise for superconductivity, but for which low temperature properties and/or substantial chemistry have not been reported.