Cyclic voltammetry experiments at minielectrodes exhibit less ohmic error for lower polarity solvents when the supporting electrolyte anion is [B(C6F5)4]- rather than one of the smaller traditional anions such as [BF4]-, [PF6]-, or [ClO4]-. Conductance measurements have been performed for [NBu4][B(C6F5)4] in tetrahydrofuran, dichloromethane, benzotrifluoride, and acetonitrile and compared with results for [NBu4]+ salts of several traditional anions in the same solvents. In solvents with dielectric constants of 10 or less, ion association constants, KA, are as much as 2 orders of magnitude lower with [B(C6F5)4]-, TFAB, as the electrolyte anion and the degree of this lowering is related to the acceptor property of the solvent. Analyses carried out on the basis of a Fuoss model attribute this fact to differences in concentrations of contact ion pairs rather than of solvent-separated ion pairs. The greater dissociation of the TFAB ion is attributed to its highly delocalized charge.

Comparison of the conductivity properties of the tetrabutylammonium salt of tetrakis(pentafluorophenyl)borate anion with those of traditional supporting electrolyte anions in nonaqueous solvents.

Precise conductance measurements on aqueous potassium chloride solutions at 0, 10, 18, and 25°C have been made under various conditions over a concentration range 10−4<c<5×10−2 mole-dm−3, yielding the conductance equations
 
$$\begin{gathered} 25^\circ C:\Lambda = 149.873 - 95.01\sqrt c + 38.48c log c + 183.1c - 176.4c^{3/2} \hfill \\ 18^\circ C:\Lambda = 129.497 - 80.38\sqrt c + 32.87c log c + 154.3c - 143.0c^{3/2} \hfill \\ 10^\circ C:\Lambda = 107.359 - 64.98\sqrt c + 27.07c log c + 125.4c - 110.3c^{3/2} \hfill \\ 0^\circ C:\Lambda = 81.700 - 47.80\sqrt c + 20.60c log c + 93.8c - 79.3c^{3/2} \hfill \\ \end{gathered} $$

 which are proposed for calibration of conductance cells.

Calibration of conductance cells at various temperatures

Size, morphology, and apparent charge of individual Na-montmorillonite particles of natural MX-80 sodium montmorillonite were investigated in the present study by the use of three coupling methods. In the first part of this work, natural and synthetic montmorillonite clays were studied with atomic force microscopy (AFM) and photo-correlation spectroscopy (PCS). Both techniques exhibit the presence of two clay populations with a high dispersion of the length distribution. Microscopic analysis of the system revealed that clay particles could be reasonably approximated at low concentrations to ellipsoidal tactoids about 1.2 nm high. Average dimensions of the first population were typically 320–400 nm long/250 nm wide and 200–250 nm long/120 nm wide for natural and synthetic clays, respectively. The second population exhibits smaller sizes: 65 and 50 nm long and 35 and 25 nm wide for natural and synthetic clays, respectively. The statistics obtained for natural clay were then verified by PCS experiments on sodium montmorillonite suspensions. Both techniques reveal an important length dispersion. However, the relative proportions of the two kinds of particles could not be established properly because of both lack of statistics and limitations of the employed techniques. In the following part, conductivity measurements were performed on dilute montmorillonite clay suspensions. Raw data were then interpreted with the sizes and morphological information gained in the first part of the present work. The apparent charge of the clay sheets was found to be 8% of the structural charge.

Study of individual Na-montmorillonite particles size, morphology, and apparent charge

Retention characteristics of organic compounds on molten salt and ionic liquid-based gas chromatography stationary phases.

1 Introduction 1 Theory of specific conductance 1 Electrical resistance and conductance 1 Definition of conductivity 2 Potassium chloride secondary standards 2 Temperature effects and instrumental temperature compensation 3 Ionic conductance 6 Concentration relationships 7 Temperature relationships 8 Effects of complexation and protonation 9 Applications to analytical quality control 10 An empirical approach in natural waters 10 Tests of the empirical model 11 Adjustments for effects of complexation 11 Calculation of the sum of conductance and the exponential correction factor (f) 11 Evaluation of/ 11 Quality control checks 12 Comparison of measured with computed specific conductance and anions with cations 12 Predicting the sum of anions or cations 13 A special case for seawater and estuarine waters 13 Notes on specific conductance measurements 14 Instrumentation 14 Procedures 14 Summary 15 References 15 FIGURES 1-5. Graphs showing: 1. Conductivity-temperature relationships for 0.01 N KG solution and 1 per mil chlorinity seawater 4 2. Percentage change in conductivity with temperature for 0.01 N KC1 solution and seawater in 1 °C increments 5 3. Values of the ratio of specific conductance to conductivity for 0.01 N KG solution and 1 per mil chlorinity seawater 6 4. Decreases in equivalent conductance of selected electrolytes with increasing concentration 8 5. Changes in limiting equivalent conductivity of selected ions with temperature 9

/pdf/specific-conductance-theoretical-considerations-and-3qiaftf33w.pdf

John E. Lind

Papers

Calibration of Conductance Cells at 25° with Aqueous Solutions of Potassium Chloride1

Conductance of the alkali halides. i. potassium chloride in dioxane—water mixtures1,2

Additions and Corrections: Calibration of Conductance Cells at 25O with Aqueous Solutions of Potassium Chloride.

Structure of Organic Melts1

Conductance of the alkali halides. ii. cesium iodide in dioxane—water mixtures1,2