Search

We have pointed out that zinc based particles obtained from ethanolic solution of a zinc acetate derivative (zinc oxy-acetate, Zn4O(Ac)6) are a mixture of nanometer sized ZnO, zinc oxy-acetate, and zinc hydroxide double salt (Zn−HDS). The knowledge of the mechanisms involved in the formation of ZnO and Zn−HDS phases, and the evolution of Zn species in reaction medium was monitored in situ during 14 h by simultaneous measurements of UV−vis absorption and extended X-ray absorption fine structures (EXAFS) spectra. This spectroscopic monitoring was initialized just after the addition of an ethanolic lithium hydroxide solution (LiOH/Zn 0.1) to the reaction medium kept under controlled temperature (40 °C). This study points out the first directevidence of the reaction between ZnO nanoparticles and unreacted zinc oxy-acetate to form a Zn−HDS phase. The dissolution of ZnO and the reprecipitation of Zn−HDS are induced by the gradual release of water mainly produced by ethanol esterification well evidenced by gas chromatography coupled to mass spectroscopy and FT−IR measurements.

The relationships between structure and nonlinear optical response at 1.5 μm in thallium(I) tellurite glasses are investigated. Usually in tellurite glasses, the introduction of a modifier ion changes the basic structural TeO4disphenoid entity progressively into a TeO3trigonal bipyramid via an intermediate TeO3+1polyhedron. This evolution leads to a decrease of the nonlinear refractive index n2. Nevertheless, if a modifier ion such as Tl+also has an ns2lone electron pair, n2increases although the same structural evolution is observed around the tellurium atoms. This result is related to the hyperpolarizability of the thallium oxygen entities, which has been evidenced by the structural study of both thallium(I) tellurite crystals and glasses of the same compositions. With this solid state chemistry approach, the highest non-linear refractive index measured at 1.5 μm (n2=9.10−19m2/W) and reported in oxide glasses has been obtained.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.