Accession Number : ADA302006

Title :   Exploratory Synthesis Employing Unusual Synthesis Approaches.

Descriptive Note : Final rept. 1 Jun 93-31 May 95,

Corporate Author : OREGON STATE UNIV CORVALLIS DEPT OF CHEMISTRY

Personal Author(s) : Sleight, Arthur W.

PDF Url : ADA302006

Report Date : 31 MAY 1995

Pagination or Media Count : 6

Abstract : One of the areas we investigated for new superconductors is reduced oxides of niobium, One unusual synthesis approach to prepare these materials has been ion exchange reactions and another has been quenching reactions from very high temperatures. Many reduced niobium oxides in A-Nb-O ternary systems where A is an alkaline or alkaline earth metal have been reported. Some examples are LiNb02 (1), NaNbl0018 (2,) BaNb80i4 (3), Ba2Nbi5032 (4) and Ca0.75Nb306 (5). Some of strongly reduced niobates contain a Nb601206 cluster with metal-metal bonding as found in NaNbl00l8 (2), BaNb8014 (3), Ba2Nb15032 (4) and Rb4Al2Nb36070 (6). These cluster compounds seemed like particularly good candidates in view of the known superconducting Mo-S cluster compounds. Furthermore, it was reported that LiNb02 changed from a semiconductor to a superconductor with a Tc = 4.5 K by deintercalation of Li+ ions (7). This confirms the potential for superconductivity in reduced niobates. Recently, we discovered a new reduced rubidium niobium oxide, Rb1.51Nb10017, with a layered structure and having a Nb6012J06 cluster (8). This compound is not superconducting down to 4.2 K, but changing the electron concentration in the cluster seemed like a worthwhile goal. The Rb+ ions occupying the interlayer space appeared to be good candidates for deintercalation or ion exchange reactions.

Descriptors :   *SYNTHESIS, *OXIDES, *NIOBIUM, *SUPERCONDUCTIVITY, IONS, METALS, LAYERS, HIGH TEMPERATURE, QUENCHING, REDUCTION, ELECTRONS, CLUSTERING, CONCENTRATION(COMPOSITION), EARTH(PLANET), ION EXCHANGE, ION ION INTERACTIONS, ALKALINITY, NIOBATES, METAL METAL BONDS.

Subject Categories : Inorganic Chemistry
      Organic Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE