Mobility Of Sodium Ions Research Articles

A nuclear magnetic resonance investigation of the mobility of sodium ions in charged cellulosic membranes

Etude pour connaitre l'etat des groupes charges de ces membranes en presence d'electrolytes

13C- and Na-NMR studies of sodium octanoate in reversed micelles

The dynamic behavior of sodium octanoate (NaO), especially that of the polar headgroups of NaO, in1-hexanol in the presence of cosolubilized water was studied by Na-NMR and13C-NMR at 24 and 25 MHz. Na-NMR data have indicated that the mobility of the sodium ions of NaO shows the lowest value at 1.2 M of NaO at a given water content, which is related to the maximum amount of water cosolubilized into the system and the change in the structure of polar headgroups of NaO.13C-NMR data have shown that the mobility of methylene carbons, No. 5 and 6 of NaO, is higher than that of methylene carbons, No. 4 and 7, and that water molecules entered among the polar headgroups of NaO affect the mobility of methylene carbons of NaO, No. 5 and 6. The hydroxyl groups of1-hexanol were found to be contact with water molecules entered among the polar headgroups of NaO, and to fill the space among the hydrocarbon chains of NaO. By assuming spherical geometry the size of water pools and the average aggregation number were calculated, and the results were discussed on the basis of13C-NMR and Na-NMR data.

Nmr Study of Sodium Ion Mobility in a Single Crystal of Na β”-Alumina and Water Effects in Polycrystalline Samples

ABSTRACTWe measured the temperature dependence of T1 in a Mg-stabilized single crystal of Na β”-alumina. A comparison with earlier measurements on Li-stabilized polycrystalline samples indicates that, below 500K, the sodium ion kinetics are not directly affected by the stabilizing element. Above 500K our measured T1 shows a dependence on sample composition. Observations of NMR linewidth and signal intensity vs. water content indicate that, at low water concentration (< 2%), all sodium is in contact with water in its conduction plane; at higher water concentrations, the additional water may be forming complexes with some of the sodium.

Mobility of Sodium Ions in Silica Glass of Different OH Content

Using 22Na as a radiotracer, mobilities of sodium ions in various types of SiO2 glasses were measured and found to depend on the OH content in the silica network. Increasing OH content in SiO2 considerably reduces the Na mobility. The effect of immobilization of Na is discussed in terms of an interaction between hydrogen and sodium ions, similar to the “mixed‐alkali effect” in alkali silicate glasses. High OH‐containing SiO2, structures display the lowest diffusivities of either sodium or hydrogen ions, thus indicating properties which are preferential in practice, such as decreasing ionic instabilities in metal‐oxide‐semiconductor devices.

Transference number and solvation studies in tetramethylurea

Transference numbers of sodium and potassium thiocyanate, have been measured in tetramethylurea at 25°C by a modified Hittorf's method in the concentration range 1.5-9.4×10-2 M. A linear relationship is observed between the cation transference number and the square root of the concentration. Combining the limiting transference numbers and limiting equivalent conductances of these two salts, ionic mobilities of sodium, potassium, and thiocyanate ions have been found to be 16.08, 15.73, and 33.04 ohm-1 cm2 mol-1, respectively. From these values ionic mobilities of other univalent ions, effective ionic radii, and solvatlon numbers have been computed. Higher solvation of cations than of anions of comparable sizes is consistent with the aprotic nature of the solvent.

ChemInform Abstract: NERNST‐EINSTEIN RELATION IN SODIUM SILICATE GLASS

AbstractDer Diffusionskoeffizient und die elektrische Beweglichkeit von (22)Na‐Ionen in einem Na‐silicatglas (25 Mol‐% N2O) werden gleichzeitig bei 300°C nach einer von Chemla benutzten experimentellen Anordnung gemessen, in der die Wärme durch ein konstantes elektrisches Gleichstromfeld erzeugt wird.

Nernst‐Einstein Relation in Sodium Silicate Glass

The diffusion coefficient and the electric mobility of sodium (22Na) ions in a sodium silicate glass (25 mol% Na2O) were measured simultaneously at 300°C in an experiment of the type used by Chemla, where the diffusion heat treatment is made in a constant dc electric field. The diffusion coefficient remained unchanged with an applied electric field. The correlation factor in the Nernst‐Einstein relation calculated from the simultaneously measured diffusion coefficient and electric mobility was 0.5±0.05.

The site of the stimulatory action of vasopressin on sodium transport in toad bladder.

Vasopressin increases the net transport of sodium across the isolated urinary bladder of the toad by increasing the mobility of sodium ion within the tissue. This change is reflected in a decreased DC resistance of the bladder; identification of the permeability barrier which is affected localizes the site of action of vasopressin on sodium transport. Cells of the epithelial layer were impaled from the mucosal side with glass micropipettes while current pulses were passed through the bladder. The resulting voltage deflections across the bladder and between the micropipette and mucosal reference solution were proportional to the resistance across the entire bladder and across the mucosal or apical permeability barrier, respectively. The position of the exploring micropipette was not changed and vasopressin was added to the serosal medium. In 10 successful impalements, the apical permeability barrier contributed 54% of the initial total transbladder resistance, but 98% of the total resistance change following vasopressin occurred at this site. This finding provides direct evidence that vasopressin acts to increase ionic mobility selectively across the apical permeability barrier of the transporting cells of the toad bladder.

Anomalously high mobility of sodium ions in SiO2films

Anomalously high mobility of sodium ions in SiO₂films

Measurement of transference numbers in molten oxide mixtures

Artificial radioactive isotopes have been used to determine the relative mobility of cations in molten oxide mixtures. A method of measuring cation transference numbers has been worked out, based on the determination of small changes of concentration in the anolyte. It has been found that in CaO·P 2O 5 and Na 2O·2SiO 2 melts the electric current is transferred exclusively by cations. In a Na 2O·CaO·4SiO 2 melt the current is also transferred only by cations. The sodium ion mobility in this melt is approximately twice as high as that of the calcium ion. In melts of the CaO·Al 2O 3·SiO 2 system the calcium transference number decreases with the increase of the Al 2O 3/CaO concentration ratio, which shows that such melts contain aluminium in the cation form.