Conductance Study of Ion Pairing of Alkali Metal Tetrafluoroborates and Hexafluorophosphates in Acetonitrile

1975 ◽  
Vol 53 (22) ◽  
pp. 3448-3451 ◽  
Author(s):  
H. L. Yeager ◽  
B. Kratochvil
Keyword(s):  
Alkali Metal ◽  
High Precision ◽  
Ion Pairing ◽  
Size Parameter ◽  
Sodium Potassium ◽  
Ion Size ◽  
Best Fit ◽  
Expanded Form

High precision conductance measurements are reported for sodium, potassium, and rubidium tetrafluoroborate and hexafluorophosphate in acetonitrile at 25 °C. The results are analyzed using the expanded form of the Fuoss–Hsia conductance equation. The ion size parameter, d, was systematically varied to obtain the value which gave best fit of the data to the equation. All salts were found to be associated, and the trends in association are discussed in terms of the ability of acetonitrile to solvate cations and anions.

Ion-pairing in aqueous solutions of peroxodisulfates

2012 ◽  
Vol 5 (2) ◽  
pp. 180-185
Author(s):  
Jan Balej
Keyword(s):  
Alkali Metal ◽  
Aqueous Solutions ◽  
Binary Solution ◽  
Ion Association ◽  
Ion Pairing ◽  
Sodium Potassium ◽  
Physico Chemical ◽  
Common Ion ◽  
Chemical Behaviour ◽  
The Common

Abstract Probable values of the degree of ion-pairing (ion-association) of aqueous solutions of alkali metal and ammonium peroxodisulfates have been calculated for various estimated values of association constants, in dependence a) on the concentration of the binary solution, b) on the concentration of the other electrolyte in the polycomponent solution with the common ion, able or not able to form ion pair, and c) on the value of the activity quotient Qa. It followed that in the presence of another component with a common cation and neglecting the influence of activity coefficients, the ion-association degree of peroxodisulfate α > 0.5 in solutions with total molality mt > 0.1 mol kg-1; as mostly Qa < 1.0, the ion-association degree is even higher so that in such cases the alkali metal and ammonium peroxodisulfates can prevailingly behave as uni-univalent electrolytes. In agreement with these results, evaluation of the solubility of sodium, potassium and ammonium peroxodisulfates in some ternary and quaternary systems has been performed under the simplified assumption of a complete ion-association to MS2O81- ions. It has been shown that the mean deviations between the calculated and observed solubilities of the crystallizing components are almost equally low as under the assumption of a total dissociation of the corresponding substances. The results indicated that the prevailing ion-association of more concentrated solutions of peroxodisufates could be taken as an acceptable approach for the quantitative evaluation of physico-chemical behaviour of systems containing peroxodisulfates.

Conductimetric studies of ionic association of tetraalkylammonium halides in iso-propanol + water mixtures at 25 °C. Part II.

1988 ◽  
Vol 66 (7) ◽  
pp. 1720-1727 ◽  
Author(s):  
Auaz Ahmad Ansari ◽  
M. R. Islam
Keyword(s):  
Dielectric Constant ◽  
Association Constant ◽  
Ionic Association ◽  
Size Parameter ◽  
Solvent Interactions ◽  
Tetraalkylammonium Ions ◽  
Conductance Data ◽  
Electrical Conductivities ◽  
Ion Size ◽  
Tetraalkylammonium Halides

Electrical conductivities of Me4NBr, Et4NBr, Pr4NBr, Bu4NBr, and Bu4PBr have been measured in isopropanol + water (2-PrOH + H2O) mixtures covering the approximate range of dielectric constant (71.40 ≥ D ≥ 19.40) at 25 °C. The conductance data have been analysed by using the Fuoss-1978 (F78) conductance equation and the results compared with those obtained from the Fuoss–Onsager–Skinner (FOS) equation. The values of the limiting equivalent conductance, Λ0, the association constant, KA, and the distance of ion-size parameter [Formula: see text] are computed from these data. A better fit of the conductance data was provided by the F78 equation. Ion–solvent interactions and effective sizes of tetraalkylammonium ions are also discussed in order to understand the magnitude of the ionic association. The overall association behaviour of these salts has been found to increase with decrease in dielectric constant of the medium.

THE THEORY OF OPTICAL ABSORPTION IN ALKALI METAL CRYSTALS

1934 ◽  
Vol 10 (3) ◽  
pp. 335-341
Author(s):  
W. H. Watson
Keyword(s):  
Absorption Band ◽  
Optical Absorption ◽  
Alkali Metal ◽  
Lattice Constant ◽  
Wave Length ◽  
Ultra Violet ◽  
Periodic Lattice ◽  
Free Electrons ◽  
Sodium Potassium ◽  
Upper Limit

The experimental results of R. W. Wood are compared with theory using the model of free electrons perturbed by the periodic lattice potential. All relevant data are collected in a table in which it is seen that in sodium, potassium, rubidium and caesium the wave-length of the upper limit of the absorption band in the visible and near ultra-violet is proportional to the square of the lattice constant, while lithium occupies an anomalous position. The facts at present available do not permit a completely definite test of the absolute values of these wave-lengths given by the theory.

Pulse Radiolysis of Alkali Metal Solutions in Ethylamine

1973 ◽  
Vol 51 (17) ◽  
pp. 2975-2986 ◽  
Author(s):  
J. W. Fletcher ◽  
W. A. Seddon ◽  
F. C. Sopchyshyn
Keyword(s):  
Alkali Metal ◽  
Pulse Radiolysis ◽  
Electron Pair ◽  
Equilibrium Constants ◽  
Distinct Species ◽  
Complexing Agents ◽  
Crown Compounds ◽  
Solvated Electron ◽  
Sodium Potassium ◽  
Extinction Coefficients

Pulse radiolysis of solutions of alkali metal ethylamides in ethylamine shows the formation of three distinct species; the solvated electron es−, the alkali metal anion M−, and a species considered to be the cation–electron pair with stoichiometry M. The three species coexist in equilibrium in accord with the equations[Formula: see text]Studies of these solutions as a function of temperature, alkali metal concentration, and added complexing agents ("crown" compounds) show that es− and M have distinct absorption spectra with the former having a maximum ≥ 1800 nm. The latter exhibit maxima at 1400 nm for Na and K, ~1400 nm for Cs, and 1600–1700 nm for Li. The corresponding M− species were observed in sodium, potassium, and cesium solutions with absorption maxima at 680, 890, and 1100 nm, respectively.Rate and equilibrium constants for the formation of M and M− vary markedly with the nature of the alkali metal. Estimates for these constants along with the extinction coefficients for the various species are summarized and compared with data obtained in alkali metal solutions.

Osmotic and activity coefficients in dilute potassium chloride solutions at 25 °C

1980 ◽  
Vol 58 (13) ◽  
pp. 1386-1387 ◽  
Author(s):  
Chai-Fu Pan
Keyword(s):  
Vapor Pressure ◽  
Potassium Chloride ◽  
Activity Coefficients ◽  
Size Parameter ◽  
Pressure Data ◽  
Vapor Pressure Data ◽  
Chloride Solutions ◽  
Ion Size ◽  
Robinson Equation ◽  
Existing Data

Osmotic and activity coefficients of dilute aqueous potassium chloride solutions are calculated from the simplified forms of the Stokes and Robinson equation. The hydration parameters in these equations are obtained from the vapor pressure data measured at higher concentration regions and the ion-size parameter is chosen as the sum of the crystallographic radii of the cation and anion of the electrolyte. The results are very satisfactory in comparison with existing data.

Volumetric properties of, and ion-pairing in, aqueous solutions of alkali-metal sulfates under superambient conditions

1996 ◽  
Vol 92 (22) ◽  
pp. 4445-4451 ◽  
Author(s):  
Marek Obšil ◽  
Vladimír Majer ◽  
Jean-Pierre E. Grolier ◽  
Glenn T. Hefter
Keyword(s):  
Alkali Metal ◽  
Aqueous Solutions ◽  
Ion Pairing ◽  
Volumetric Properties
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