Conduction minimum

Fuoss, R. M. Kraus, C. A. (1933). Properties of electrolytic solutions. IV. The conductance minimum and the formation of triple ions due to the action of Coulomb forces. Journal of the American Chemical Society, 55, 2387-99. 

The role played by the micro Wien effect in dissociating the disodium spinide with increasing concentration beyond the conductance minimum is strongly indicated by the temperature coefficient of the conductance of solutions of sodium and potassium in liquid ammonia. Here we have data for the temperature coefficient of sodium and potassium from relatively dilute solutions up to saturation. 

Figure 1 Equivalent conductance vs. logarithm of concentration of LiC104 and LiBF4 in methyl formate illustrating conductivity minimum with low dielectric permittivity solvent. (From Venkatasetty [30], reprinted by permission of the Electrochemical Society.)...

The condition for the conductance minimum is found by differentiating equation (87) with respect to c and setting the result equal to zero this procedure gives... 

The fact that the concentration at which the conductance minimum occurs decreases with decreasing dielectric constant of the solvent is shown by the results in Fig. 21 (p. 53). In media of very low dielectric... 

Weingartner, H., Weiss, V.C., and Schroer, W. Ion association and electrical conductance minimum in Debye-Htickel-based theories of the hard sphere ionic fluid. J. Chem. Phys., 2000, 113, p. 762-70. 

The equation necessary for their interpretation is 5.8.7. At concentrations well below the conductance minimum, where the presence of ionic triplets may be disregarded, the cation-constituent transference number (with LiBr as the example) becomes ... 

If at much higher molarities, above the conductance minimum, the content of single ions is insignificant in comparison with the concentration of triple ions, then CLiBrLi+ = BrLiBr- and eqn. 5.8.7 approximates to... 

FIGURE 2b Example dynamic systems relationship from Entelos Asthma PhysioLab computer simulations, showing airway conductance minimum as a function of anti-IgE dose level and period. SOURCE Reprinted with permission from Entelos, Inc. 

Similarly, if association of ionic species occurs, the interaction is accompanied by a decrease in the concentration of free charge carriers, giving rise to a conductance minimum in the titration curve. 

The essential features of the tunneling conductance curves, that is (i) their symmetry with respect to polarity reversal of the bias and (ii) the increased steepening of the conductance minimum at zero bias with decreasing temperature, have been confirmed for a-Ge and a-Si by Smith and Clark (1972) and for a-Si by Sauvage and Mogab (1972). 

At concentrations far below the conductivity minimum (c 10 mol dm in Fig. 6), triple-ion formation can be neglected. Data analysis is possible with the help of Eqs. (65), in agreement with pairwise additive potential functions, and yields the values of A in Table III. The ion-pair association constants of these plots agree well with the determined independently at higher concentrations with the help of Eq. (72), which takes into account both ion-pair and triple-ion formation. No method is known for the determination of the values of data analysis yields only the product which the quantity is commonly estimated to be 2 A /3. Both ion-pair... 

Here, the conductivity minimum occurs at a molar ratio of 0.98 instead of 1.0, but atitempts to isolate the potassium salt were not successfuP ... 

Fig. 7.2 The conductivity behaviour of indium selenide and gallium selenide as determined by Okada and Ohno [22], The conductivity minimum occurs at a composition between InSe and ln2Se3, rather than at stoichiometry as expected. The anomalous peak at IniSes appears to disappear with increasing temperature (Reprinted by permission of Physical Society of Japan. Okada and Ohno [22])...

Thns, we conducted minimum evolution (ME) searches on LogDet distances using PAUP " 4.0 beta 2 (written by D.L.Swofford). In order to acconnt for the observation of rate heterogeneity across different nucleotide sites in these rRNA sequences (i.e., Mallatt and Sullivan 1998), we used an invariable-sites model. Although Mallatt and... 

Thermoelectric power (a) measurements on slightly Eu-rich as-grown samples down to 7 K indicate that changes in the conductivity as a function of temperature and magnetic field above lOkOe are mainly caused by changes in the mobility, whereas the conductivity minimum and the negative magnetoresistance at H<10 kOe at temperatures below 20 K are... 

---