Configurational charges

In effect, the lanthanide contraction has shrunk these elements. Since electronic configuration, charge, and ionic size generally determine chemical behavior, we should expect that Zr+4 and Hf+4 have extremely similar behaviors and that the same should be true for Nb+5 and Ta+5. Such similarities are indeed observed and prove exceedingly troublesome in the course of chemical separations. 

In other studies, the above research group synthesised a number of related one-and two-station, photoactive [2]-rotaxanes incorporating either ferrocene or anthracene stoppers or a combination of each type. In these systems, the terminal stoppers associate with the exterior of the bis(4-4 -bipyridinium)cyclophane tetracation via 7U-stacking. Such proximity has obvious implications for the required rapid electron-transfer to a terminal (ferrocenyl) group in order to be competitive with the simple charge recombination process discussed previously. The relationship between the photoactivity, electron-transfer behaviour and concomitant configurational charges in the above systems has now been described in some detail. " ... 

An agonist, by virtue of the molecular information it contains (e.g., size, 3D configuration, charge distribution, hydrogen- or ionic-bonding residues, chirality), selectively binds to a complementary 3D surface or binding site domain formed by amino acid residues of a receptor protein and initiates a... 

Fig. 1.79. Relaxed atomic configurations of H2O and O2 coadsorbed on free Ans and Au3o clusters (top) and on Aug/MgO(lOO) (bottom). For the free and snpported Ang cases, the difference-charge-density between the compiete adsorption system and the separated Au8/MgO(100) and O2-H2O complex are displayed, superimposed on the atomic configuration. Charge depletion is shown in dark grey and charge accumulation in gray-white. Light grey, dark, and white spheres correspond to An, O, and H atoms, respectively...

The rate of the substitution of a given solvent molecule in the inner coordination sphere depends mainly on the nature (electron configuration, charge and size) of the metal ion rather than that of the incoming ligand. 

Additional hieh-integritv requirements l C comms will be to other hIgh-Integrity systems and to control systems only, and unidirectional Security for configuration charges... 

Point defects and complexes exliibit metastability when more than one configuration can be realized in a given charge state. For example, neutral interstitial hydrogen is metastable in many semiconductors one configuration has H at a relaxed bond-centred site, bound to the crystal, and the other has H atomic-like at the tetrahedral interstitial site. 

The unequal distribution of charge produced when elements of different electronegativities combine causes a polarity of the covalent bond joining them and, unless this polarity is balanced by an equal and opposite polarity, the molecule will be a dipole and have a dipole moment (for example, a hydrogen halide). Carbon tetrachloride is one of a relatively few examples in which a strong polarity does not result in a molecular dipole. It has a tetrahedral configuration... 

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