Barium titanium oxide

Campion, J, F., Payne, D. A., Choe, H. K., Maurin, J. K., and Wilson, S. R., Synthesis of bimetallic barium titanium alkoxides as precursors for electrical ceramics. Molecular structure of the new barium titanium oxide alkoxide Ba4Tii30i2(OC2H40Me)24, Inorg. Chem., 30, 3245 (1991). 

CAS 12047-27-7 EINECS/ELINCS 234-975-0 Synonyms Barium metatitanate Barium titanium oxide... 

A wide array of ferroelectric, piezoelectric and pyroelectric materials have titanium, zirconium and zinc metal cations as part of their elemental composition Many electrical materials based on titanium oxide (titanates) and zirconium oxide (zirconates) are known to have structures based on perovskite-type oxide lattices Barium titanate, BaTiOs and a diverse compositional range of PZT materials (lead zirconate titanates, Pb Zr Tij-yOs) and PLZT materials (lead lanthanum zirconate titanates, PbxLai-xZryTii-yOs) are among these perovskite-type electrical materials. 

Barium titanate, BaTi03, is probably the most widely studied ferroelectric oxide. Extensive studies were conducted on this compound during World War II in the United States, England, Russia, and Japan, but the results were not revealed until after the war. Barium titanium(IV) oxide was found to be a ferroelectric up to a temperature of 120°C., which is its Curie point. Above 120°C., barium titanium(IV) oxide has the cubic perovskite structure, and below this temperature the oxygen and titanium ions are shifted and result in a tetragonal structure with the c axis approximately 1% longer than the a axis. Below 0°C., the symmetry of barium titanate becomes orthorhombic, and below —90°C., it becomes trigonal. 

Thin reaction layers (<10 p.m thick) coating spinel surfaces that are composed of titanium oxides and phlogopite. These phases dominate the budget for niobium, tantalum (45-60%), and mbidium plus barium (30-80%) in all the xenoliths studied. 

Large scale manufacture of BaTiOj from barium carbonate and titanium oxide... 

Exploration of alkaline earth/metal oxide catalysts and other metal/metal oxide catalysts has been continued at Union Carbide. As an example, after over 350 hours of methane coupling with a 5 wt% barium carbonate on titanium oxide (with ethyl chloride in the feed gas), a C2 yield of 22%, a Cj selectivity of 58%, and an ethylene/ethane ratio of 8 1 were obtained. The coupling catalysts were comparable in selectivity, activity, and Cj yield to the better literature catalysts, but provide hundreds of hours of stable operation in the oxidation of methane to Cj s. These catalysts require the presence of a small amount of halides, either as a catalyst component or as a periodic or continuous additive to the catalyst. The chloride appears to serve three distinct roles, resulting in suppression of carbon dioxide formation, increased rates to Cg products, and higher ethylene-to-ethane product ratios. There have been numerous other recent reports. 

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