Bismuth -oxide superconductors

The layer-type structures and chemical nature of the constituents of the bismuth and thallium-based cuprate superconductors - notably the lone-pair stereochemistry of Bis+, variable valence of copper, and considerable exchange among some of the cation sites - combine to make structural non-ideality, nonstoichiometry, and phase intergrowth the rule rather that the exception in these families of materials. These features, as well as the probable metastability of the phases (and possibly all high-temperature oxide superconductors), also contribute to the difficulties typically encountered in preparing single-phase samples with reproducible properties and compositions. 

The Chemistry of High Tc in the Bismuth Based Oxide Superconductors BaPbi.xBix03 and Bai xKxBi03... 

Bismuth Based Oxide Superconductors BaPbj.jjB Og and Ba1.xKxBi03 349... 

Bismuth Based Oxide Superconductors BaPbj B Oj and Ba1.xKxBi03 351... 

Bismuth Based Oxide Superconductors BaPbl xBix03 and Ba1.xKxBi03 353... 

Bismuth Based Oxide Superconductors BaPb1.xBix03 and Ba1.xKxBi03 355... 

A method that can distinguish between the oxidation states Cus+ and Bi5+ in bismuth-based superconductors has been described (33). Bi5+ (BiOs") can oxidize Mn2+ to Mn04", while Cus+ is not a strong enough oxidizing agent to accomplish this task. 

Bismuth is an important element in many of the new high-temperature, oxide superconductors and in a variety of heterogeneous mixed oxide catalysts. Some of the methods employed in the preparation of these materials, namely sol-gel and chemical vapor deposition processes, require bismuth alkoxides as precursors and a number of papers on these compounds have recently been published.1 One synthetic route to bismuth alkoxides, which avoids the more commonly used trihalide starting materials and the often troublesome separation of alkali metal halides, involves the reaction between a bismuth amide and an alcohol according to the following equation ... 

The one-meter-long conductor, based on a bismuth-strontium-calcium-copper oxide superconductor, carries over 2300 amps of direct current at liquid nitrogen temperatures (77 K). This is more than twice the current-carrying capability of conventional copper cables. 

The homologous series of bismuth copper oxide superconductors Bi2Sr2Can iCUn05+2n-l-x 1,2,3) consisting of a layer... 

---