Alkaline niobates

Synthesis of niobates and tantalates of alkaline metals at high temperatures may result in the products with unintended stoichiometry because of high volatility of alkaline metal (especially lithium) oxides. Therefore, their synthesis in the form of efficiently sintering powders presents a serious problem. Films of alkaline niobates and tantalates can find wide range of applications in acousto- and optoelectronics and are usually prepared by rf-sputtering techniques, also giving rise to stoichiometry problems. 

Delgado, E.J., Gordon, A.L., and Jimenez, R. (2013) Catalytic oxidation of soot over alkaline niobates. /. Alloy Compd., 551,... 

Alkaline niobates and tantalates, when treated with H2O2, precipitate Alk3[M (77 -02)4]. These release O2 slowly, or explosively at 80°C. An acid, perhaps [ Nb0(02)0H 2] -aq, arises on adding H2SO4. 

Perovskites have the chemical formula ABO, where A is an 8- to 12-coordinated cation such as an alkaU or alkaline earth, and B is a small, octahedraHy coordinated high valence metal such as Ti, Zr, Nb, or Ta. Glass-ceramics based on perovskite crystals ate characteri2ed by their unusual dielectric and electrooptic properties. Examples include highly crystalline niobate glass-ceramics which exhibit nonlinear optical properties (12), as well as titanate and niobate glass-ceramics with very high dielectric constants (11,14). 

Pechini, M., Method of preparing lead and alkaline earth titanates and niobates and coating method using the same form a capacitor, U.S.Pat. 3330697, July 11, 1967. 

Addition of excess of potassium thiocyanate to an alkaline solution of a niobate, followed by zinc and concentrated hydrochloric acid, produces a golden-brown colour which may be almost red in the presence of larger quantities of niobium. It is stated that ndther tantalum nor titanium gives any coloration under the same conditions.3 Addition of... 

Orthoperoxometallates A3[Mf02)4] precepitate from alkaline solutions of niobates or tantalates on additon of The four O2 groups are linked side-on to the metal in... 

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