Complex 3D macrostructured nanoparticles are transformed from amorphous silica into pure polycrystalline α-quartz using catalytic quantities of alkaline earth metals as devitrifying agent. Walls as thin as 10 nm could be crystallized without losing the architecture of the particles. The roles of cation size and the mol% of the incorporated devitrifying agent in crystallization behavior are stud...

In a theoretical study of a "defect perovskite" structure of stoichiometry AeTiO(2) (AE = alkaline earth metal, Be, Mg, Ca, Sr, and Ba), we find substantial Ti-Ti bonding tuned by the size of the Ae(2+) cation. The bonding is one-dimensional, partially sigma, partially pi. These formal d(2) systems are expected to be nonmagnetic and metallic. A competing (for same Ae) structural alternative, an...

We calculate ab–initio the electronic states and the Born dynamical charge Z of the alkaline–earth oxides in the local–density approximation. We investigate the trend of increasing Z values through the series, using band–by–band decompositions and computational experiments performed on fake materials with artificially–modified covalence. The deviations of Z from the nominal value 2 are due to t...

In this study the binding abilities of 1,3-calix[4]biscrown-6 (L) toward Ba2+ and Ca2+ have beenestablished in methanol by spectrophotometric measurements at 25±0.1 °C and 0.01 M ionicstrength, and with using Specfit computer program; stability constants for 2 : 1, metal : ligandcomplexes has been estimated

Bond-length distributions have been examined for 55 configurations of alkali-metal ions and 29 configurations of alkaline-earth-metal ions bonded to oxygen, for 4859 coordination polyhedra and 38 594 bond distances (alkali metals), and for 3038 coordination polyhedra and 24 487 bond distances (alkaline-earth metals). Bond lengths generally show a positively skewed Gaussian distribution that ori...

Two-dimensional (2D) electrides, emerging as a new type of layered material whose electrons are confined in interlayer spaces instead of at atomic proximities, are receiving interest for their high performance in various (opto)electronics and catalytic applications. Experimentally, however, 2D electrides have been only found in a couple of layered nitrides and carbides. Here, we report new ther...

INTRODUCTION In 1975, Small and coworkers first introduced the concept of ion chromatography (IC) that allowed the sensitive detection of ions using suppressed conductivity detection. A significant portion of this work was dedicated to cation analysis. The original components described by Small et al. for the separation of cations included a low-capacity, sulfonated polystyrene/ divinylbenzene ...

Novel 2-benzothiazole-, 4-pyridine-, and 2- and 4-quinoline-based styryl dyes containing an N-methylbenzoaza-15(18)-crown-5(6)-ether moiety were synthesized. A detailed electronic spectroscopy study revealed high performance of these compounds as optical molecular sensors for alkali and alkaline-earth metal cations. They were shown to considerably surpass analogous chromoionophores based on N-p...

The ability of dead cells of endophytic Drechslera hawaiiensis of Morus alba L. grown in heavy metals habitats for bioremoval of cadmium (Cd2+), copper (Cu2+), and lead (Pb2+) in aqueous solution was evaluated under different conditions. Whereas the highest extent of Cd2+ and Cu2+ removal and uptake occurred at pH 8 as well as Pb2+ occurred at neutral pH (6-7) after equilibrium time 10 min. Ini...