In this work, we analyze the geometry and electronic structure of the [X(n)M(3)](n-2) species (M = Be, Mg, and Ca; X = Li, Na, and K; n = 0, 1, and 2), with special emphasis on the electron delocalization properties and aromaticity of the cyclo-[M(3)](2-) unit. The cyclo-[M(3)](2-) ring is held together through a three-center two-electron bond of sigma-character. Interestingly, the interaction ...

The isothermal bulk modulus $$K_{{T_{m}}}$$ and surface tension γm of liquid metals at the melting point increase with decreasing atomic size a, these dependences are similar to one another. It is shown that transition a hexagonal closed-packed body-centered cubic structure concentrated above γm− regression line, face-centered below this line. In alkali, alkaline earth, rare earth metals, chang...

South African Palabora vermiculite was modified by ion exchange with ammonium and selected alkali metal and alkaline earth metal ions. In the exchanged vermiculite with ammonium ions, it was found that ammonia and water were the blowing agents and they were simultaneously released during thermal degradation. In the increasing ionic potential series: Na, Ba, Ca and Mg, it was found that the onse...

The cluster compounds (NH4)4[Nb6Cl12(N3)6](H2O)2 (1) and Na1.15(3)La0.85(3)[Nb6Cl12(N3)6](H2O)13(1) (2) have been synthesized by the reaction of an aqueous solution of Nb6Cl14 with an excess of NaN3 and the respective chloride salts. 1 crystallizes isotypically to the other alkali metal cluster azides in the space group P1̄ (no. 2) with the lattice parameters a = 908.97(8), b = 932.78(8), c = 10...

A physical model of selective "ion binding" in the L-type calcium channel is constructed, and consequences of the model are compared with experimental data. This reduced model treats only ions and the carboxylate oxygens of the EEEE locus explicitly and restricts interactions to hard-core repulsion and ion-ion and ion-dielectric electrostatic forces. The structural atoms provide a flexible envi...

In the present study we have synthesized new binuclear complexes of alkali and alkaline earth metal salts with interaction of stable metal chelates of isonitrosopropiophenone of Ni(II) & Cu(II) having general formula [Ma(INPP)2.MbL] and [Ma(INPP)2.MbX] for alkali metal adducts and [ Ma(INPP)2.MbL2] and [ Ma(INPP)2.MbX2] for alkaline earth metal adducts where Ma=Ni (II) or Cu(II) and Mb =Li+ , N...

Diazacrown ethers having two carbodithioate groups were synthesized, and their spectrophotometric properties were studied. Diammonium 1,4,10,13-tetraoxa-7,16-diazacycrooctadecane-N,N'-bis(carbodithioate) (DA18CC) and ammonium 1,4,10-trioxa-7,13-diazacycropentadecane-N,N'-bis(carbodithioate) (DA15CC) reacted with most heavy-metal ions through their two carbodithioate groups, and also reacted wit...

This study was carried out in the Ravar plain, a typical arid zone in southeastern Iran, with the objectives of evaluating hydrochemical quality of the groundwater resources and identifying the processes that modify the groundwater composition. Groundwater samples were collected from representative wells spread over the study area. Major cations and anions along with physico-chemical parameters...

In the chelating ion exchanger synthesized, the amino group of histidine is attached chemically via the azide method to the carboxyl group of Amberlite IRC-50. A flow system based on a spectrophotometric detector, with 4-( 2-pyridylazo)resorcinol as reagent, is described for fast assays of eluted cations. The pH dependence of the metal extraction is reported for Ag(I), Au(III), Cu(II), Fe(III),...