Sodium charge distribution

Describe the similarities and differences in geometries, charge distributions and electrostatic potential maps for cyclopentadienyl sodium, cyclopentadiene and cyclopentadienyl anion. 

A polyelectrolyte solution contains the salt of a polyion, a polymer comprised of repeating ionized units. In dilute solutions, a substantial fraction of sodium ions are bound to polyacrylate at concentrations where sodium acetate exhibits only dissoci-atedions. Thus counterion binding plays a central role in polyelectrolyte solutions [1], Close approach of counterions to polyions results in mutual perturbation of the hydration layers and the description of the electrical potential around polyions is different to both the Debye-Huckel treatment for soluble ions and the Gouy-Chapman model for a surface charge distribution, with Manning condensation of ions around the polyelectrolyte. 

Fig. 6.4 The radial charge distribution of the screening clouds around sodium, potassium, magnesium, and aluminium ions in free-electron environments of the appropriate equilibrium metallic densities. The arrows mark the positions of the first nearest neighbours in hep Mg and fee Al, the first and second nearest neighbours in bcc Na and K. (After Rasolt and Taylor (1975) and Dagens et al. (1975).)...

Crown or solvent complexation leading to loose ion pairs can by itself cause a drastic change in the charge distribution of the anion. A good example is found in reaction 4 studied by Boche et al (19). At room temperature the sodium enolate tight ion pair with... 

The negative charge distribution in the adducts was evaluated on the basis of the chemical shift values and found to be nearly 75% concentrated on the nitrogen atom. In the reactions of l-ethoxycarbonyl-l,4-dihydropyridines with organosodium and organopotassium compounds, the resulting metal-associated (j-adducts were not soluble in aliphatic hydrocarbons alone but were made so by addition of 18-crown-6. This behavior would support ionic structures for the potassium and sodium adducts. 

A tetraanion salt (84 )/4M has been formed by stepwise four-electron transfer from 4,7,12,15-tetrastyryl[2.2]paracyclophane (8) to lithium, sodium, and potassium metals in [2Hx]THF at 220 K a strong effect of the cyclophane hub on the charge distribution has been demonstrated and the influence of o1, o2, o3, o4-tetramethyl and px, p2,pi,pA-tetramethoxy substituents on the ease of reduction has been tested.9... 

The charge distribution in sodium forms of faujasites was investigated by Beran and Dubsky (102, 103). A fragment of the potential surface corresponding to the localization of Na+ ion near two four-membered windows of X- and Y-type zeolites (S, sites) was calculated, and the estimated activation energy for the ion migration between two equivalent positions was found to be 5 kcal/mol. 

The charge distribution in pyridine leads to deactivation for electrophilic substitution, the least for the position 3 (formation of 3-bromopyridine) at higher temperatures mainly 2-bromo-pyridine is produced by radical substitution. With sodium amide 2-aminopyridine is produced as a nucleophilic substitution reaction. 

UV-Vis, H and NMR study of monometallic salts of 9,10-dihydroan-thracene and its 9,10-disubstituted derivatives in THE, showed lithium 9-phenyl-9,10-dihydroanthracene-9-ide, lithium 9,10-dimethyl-9,10-dihydroanthracenide and lithium 9,10-diphenyl-9,10-dihydroanthracenide exist as a solvent separated ion pair (SSIP). Sodium, potassium, rubidium and cesium 9,10-dihydroanthracenides, 9-methyl-9,10-dihydroanthracene-10-ides and 9-cyano-9,10-dihydroanthracenides exist as contact ion pairs (CIP) in solution. A model, taking into account the geometry and charge distribution, for the transition of CIP of alkali metal salts of 9,10-dihy-droanthracene and its derivatives into SSIP is proposed [283]. 

The applicability of the major concepts of the PQS model to iron(II) complexes is associated with an axial symmetry of the EDD about the iron atom. Such symmetry is important to establish the correlation between QS and the geometry of the coordination environment. In the case of octahedral complexes, this assumption was confirmed by the results of calculations and by the experimental measurements of the EDD. For example, the deformation electron density (DED) map for sodium nitroprusside (FeBsA geometry) demonstrated a nearly axial charge distribution around the iron atom in the equatorial plane [278]. 

Full knowledge of the charge distribution of a molecule requires specification of the charge density at all points. For some purposes the charge density provides excess information thus, the potential outside a sodium ion is independent of the distribution of the electrons, and the interaction of a molecule with a uniform external field is determined by its dipole moment and dipole polarizabilities. The electric multipole moments characterize the charge distribution the first three are defined as follows ... 

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