Cations In Glasses Research Articles

Determination of gibbs free energy of transfer for alkali metal chlorides from water to water dimethylsulphoxide mixtures using cationic glass electrodes—a test for the method

Determination of gibbs free energy of transfer for alkali metal chlorides from water to water dimethylsulphoxide mixtures using cationic glass electrodes—a test for the method

Solvation in hydroorganic media—II. Gibbs free energy of transfer for HCl and comparison between Rb + and H + ions

A previously derived method for the determination of Gibbs free energies of transfer of alkali chlorides using cationic glass electrodes is applied to the transfer of HCl, and results for the transfer of HCl from water to a large number of water-organic solvent mixtures are reported. The accuracy of the proposed method is critically discussed. Relations for the Gibbs free energies of transfer of RbCl and HCl in various aqueous organic media, based on some classical models, are compared. A basicity scale for the organic cosolvents used was derived, based on the theory of Pleskov[19].

Solvation in hydroorganic media—I. Gibbs free energy of transfer for RbCl from cationic glass electrode measurements

A previously derived method for the determination of Gibbs free energies of transfer for the alkali metal chlorides using cationic glass electrodes is applied to the transfer of RbCl. Gibbs free energies for the transfer of RbCl from water to a number of water-organic solvent mixtures are reported and discussed in terms of solvation. The interest and validity of the proposed method is demonstrated.

Continuous assays of l-asparaginase by coupling with glutamic dehydrogenase and by cationic glass electrode

Continuous assays of l-asparaginase by coupling with the glutamic dehydrogenase reaction and by cationic glass electrode are described. The procedures are about equally sensitive although the latter is simpler and a more direct assay. The two methods gave identical specific activity values for a purified preparation of Escherichia coli l-asparaginase.

ChemInform Abstract: SOLUTE‐SOLVENT INTERACTIONS IN WATER‐TERT.‐BUTYLALCOHOL MIXTURES PART 4, TRANSFER FREE ENTHALPIES OF ALKALI METAL CHLORIDES FROM CATIONIC GLASS ELECTRODES MEASUREMENTS

Chemischer InformationsdienstVolume 5, Issue 35 Physical Inorganic Chemistry ChemInform Abstract: SOLUTE-SOLVENT INTERACTIONS IN WATER-TERT.-BUTYLALCOHOL MIXTURES PART 4, TRANSFER FREE ENTHALPIES OF ALKALI METAL CHLORIDES FROM CATIONIC GLASS ELECTRODES MEASUREMENTS Y. POINTUD, Y. POINTUDSearch for more papers by this authorJ. JUILLARD, J. JUILLARDSearch for more papers by this authorJ.-P. MOREL, J.-P. MORELSearch for more papers by this authorL. AVEDIKIAN, L. AVEDIKIANSearch for more papers by this author Y. POINTUD, Y. POINTUDSearch for more papers by this authorJ. JUILLARD, J. JUILLARDSearch for more papers by this authorJ.-P. MOREL, J.-P. MORELSearch for more papers by this authorL. AVEDIKIAN, L. AVEDIKIANSearch for more papers by this author First published: September 3, 1974 https://doi.org/10.1002/chin.197435005Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume5, Issue35September 3, 1974 RelatedInformation

Solute-solvent interactions in water tert-butylalcohol mixtures—IV. transfer free enthalpies of alkali metal chlorides from cationic glass electrodes measurements

Transfer free enthalpies of alkali metal chlorides from water to water tert-butylalcohol mixtures are obtained. Silver-silver chlorides electrodes and glass electrodes sensitive to alkali metal ions are employed. The use of the glass electrode is justified theoretically and practically. The selectivity of the glass electrode is considered. Similar results are obtained for other hydro-organic mixtures and compared to previous determinations using other methods.

Electron-transfer Kinetics of Transition-metal Complexes in Lower Oxidation States. Part II. The Electrochemical Electron-transfer Rate of the Cr(bipy)3+/Cr(bipy)3 System as Measured by the Galvanostatic Double-pulse Method

Abstract The kinetic parameters of the electron-transfer reaction, Cr(bipy)3++e\ightleftharpoonsCr(bipy)3, were measured by the galvanostatic double-pulse method at a dropping mercury electrode in N,N-dimethylformamide. The apparent and the corrected standard rate constants were 1.0±0.2 and 0.3 cm s−1 respectively, and the transfer coefficient was 0.6±0.1 at 25 °C. These rate constants were discussed in comparison with the corresponding homogeneous rate constant on the basis of the theoretical equation of Marcus. They were quite inconsistent with the value, 103 cm s−1, predicted from the corresponding homogeneous rate constant. The polarograms of Cr(bipy)3+ and Cr(bipy)3 exhibited three waves with half-wave potentials of −0.21, −0.65 and −1.19 V vs. a cationic glass electrode. The diffusion coefficients of these complexes, as determined polarographically, were identical: 3.2×10−6 cm2 s−1 at 25 °C.

Some Considerations on the Diffusion Profile of Monovalent Cations in Glass

Diffusion data of monovalent cations in glass have been analysed on the basis of several theoretical equations. Main results are as follows:1. It was predicted that the following characteristics were applicable to the inter-diffusion data; (1) time-dependence of the depth of diffusion, (2) comparison of the diffusion profile with standard profiles derived by Fujita, and (3) linear relationship between the reciprocal of the inter-diffusion coefficient and the ion concentration. Many of the present data were, however, found not to satisfy the linearity (3).2. Self-diffusion coefficient of Na+, DNa*, derived from extrapolation of the curve (3), differs largely from the one, measured with isotope 24Na. It is attributed to the difference of the field of diffusion in both cases, i.e., the DNa* itself is a function of concentration. Temperature-dependence of DNa* is larger than expected.3. Partition coefficient of monovalent cation between the molten salt and the glass varies largely depending on the cation species. However, linear relationship is held between the reciprocals of the equilibrium concentrations of the distributed ion in both phases. Activity coefficients of the ions in glass can be approximately calculated from these equilibrium data and heat of mixing of molten salts in literatures.4. Although the linearity (3) is somewhat improved by introducing these coefficients, the discrepancy is still large. The variations of ratio DNa*/DM* (M=K, Ag) are discussed on the basis of the irreversibility of the diffusion processes.

A Rapid Method of Determining Ammonium in Water With a Univalent Cation Glass Electrode

The use of a univalent cation glass electrode for determining ammonium in water is described. The method enables direct determination of ammonium ion in concentrations above 0.5 mg/liter without any dilution or pretreatment of sample. A constant background of Na+ and K+ in samples is required, with concentration of potassium being lower than that of ammonium. For several types of natural and enriched waters with ammonium content up to 40 mg/liter NH4-N, the mean error by the method was ±4.9%.

Transition Metal Ions as Spectroscopic Probes for Detection of Network Structure in Novel Inorganic Glasses

Spectra of divalent transition metal ions in ZnCl2, KOAc-Ca(OAc)2, KNO3-Ca(NO3)2, and K2SO4-ZnSO4 glasses are presented. Ions with low octahedral site preference energies (e.g. CO2+) can be used as “probes” for divalent cations in glass and can indicate the presence or absence of network structures. Thus ZnCl2 glass has a tetrahedral network structure, analogous to vitreous BeF2, but KOAc-Ca(OAc)2 and KNO3-Ca(NO3)2 glasses contain potassium ions and discrete acetatocalcate(II) and nitratocalcate(II) “complex ions.” The structure of acetate and nitrate glasses is discussed in terms of the ideal glass concept.

Cation Replacement Studies on Heteroionic Bentonitic Clay Fractions Using Specific Ion Glass Electrodes

AbstractCentrifuged fractions, ranging in size from 2·0 to 0·05 μ of a Wyoming bentonite, Bentonita de Durango from Mexico, and Helms clay from Texas were studied. The variation in replacement of Na+, Ca2+, Mg2+, K+, and H+ from these heteroionic clay systems under specific equilibrium conditions of salt concentrations was measured.The displacement cation distribution was monitored by using specific ion glass electrodes, such as a sodium ion electrode, a cationic glass electrode, a calcium ion electrode and a Tektite electrode. Some factors affecting the exchange reactions are discussed and application of findings to drilling and production techniques is indicated.

Cationic glass electrode response to alkali metal ions in nonaqueous solvents

Cationic glass electrode response to alkali metal ions in nonaqueous solvents

Experimental and theoretical studies of low-voltage electronluminescence of ZnS single crystals

Sub-critical crack growth in various kinds of metaphosphate glasses was investigated by using DCDC (Double Cleavage Drilled Compression) technique. The crack growth measurements were only being made in Region III, or in an inert environment. In order to evaluate intrinsic crack growth behaviors in Region III, crack propagation tests were performed in dehydrated heptane, and the crack velocity, v, was plotted as a function of the stress intensity factor, KI. Fracture toughness of glass was also estimated from a stress intensity factor at a given crack velocity. For binary metaphosphate glasses (50MO · 50P2O5, M = Zn, Mg, Ca, Ba), fracture toughness increases in the order of Mg > Ca > Zn > Ba. However, the slope of KI–v curve is almost unchanged. In the case of aluminum containing metaphosphate glasses, with increasing aluminum content, fracture toughness increases and the slope of KI–v curve becomes smaller, regardless of the type of divalent cations in glass. It is concluded that an addition of aluminum ions into metaphosphate glass results in both high toughness and easy fatigue. In addition, the structural role of aluminum ions on the intrinsic sub-critical crack growth is discussed in terms of the models of atomistic bond rupture.

The determination of the ferrocyanide—ferricyanide standard electrode potential at 25°C in cells without liquid junction using cation-sensitive glass electrodes

A new method for the determination, in cells without liquid junction, of standard potentials of electrodes that involve both soluble oxidized and reduced species is described. The method involves the use of cationic glass electrodes in double cells and has been used to determine, free from liquid junction potentials the standard potential of the Fe(CN) 6 4−(aq)/Fe(CN) 6 3−(aq) electrode. The value obtained, + 361·0 ± 0·5 mV at 25°C, is compared with previously reported values.

A calibration system for total pressure gauges in the range 10 −3-10 −5 torr : J G Bannenberg and A Tip, FOM-Institute for Atomic and Molecular Physics, Amsterdam, Netherlands

The structure of nuclear glasses and of simplified surrogates has been investigated using complementary diffraction and spectroscopic methods, together with numerical modeling. The diversity of structural surroundings of cations in glasses is reviewed at various scales. Cations usually occur in smaller sites in glasses than in crystals, with unusual site geometries such as 5-coordination. These sites may correspond to different structural positions. Network forming and networking situations illustrate the existence of a well-defined relationship with the glassy network, with cations improving glass stability. The complementary charge-compensation may sometimes give rise to a competition between cations. In that case, the cation may lose its stabilizing character and become a nucleating agent, as observed for “chameleon” elements, the coordination of which and hence the structural properties may change as a function of glass composition. Eventually, at the mesoscale, the heterogeneous distribution of cations has been recently visualized, providing keys to understand the nucleation processes in glasses.

CATIONIC GLASS ELECTRODE RESPONSE IN AQUEOUS SOLUTIONS OF SODIUM CHLORIDE AND POTASSIUM CHLORIDE.

The selectivity of glass electrodes suitable for potassium-ion measurements depends on the age of electrodes and the composition of the solution. An empirical equation describing the electrode potential as a function of solution composition is given for practical application in solutions containing both sodium and potassium.

Composition of Interstitial Waters of Modern Sediments

Interstitial waters were squeezed from several hundred samples of modern oceanic sediments in twenty-two cores from six general areas: the central equatorial Atlantic Ocean, the southwest Atlantic, the northwest Atlantic, the continental shelf off Cape Cod, Massachusetts, the Gulf of California, and the Experimental Mohole (Guadalupe site). Samples were analyzed for Ca and Mg (versene titration), Na and K (cationic glass electrodes), Cl ($$AgNO_{3}$$ titration), and $$SiO_{2}$$ (molybdate colorimetry). Direct determinations of pH and saturometry were made on board ship. Chlorinity varies about a mean close to that of average sea water but shows significant variations both within and between cores from different locations. Chlorinity differences are probably due to semipermeable behavior of compacting clays rather than to "paleosalinities." Increase in $$CO_{2}$$ pressure that results from decay of organic matter is the cause of the lowering of pH in almost all cores. Ca and Mg are similar to that in sea water but Mg is slightly depleted as a result of takeup by chlorites and possibly incipient dolomitization. Na varies sympathetically with chlorinity, but in most samples K is enriched as a consequence of continued hydrolysis of detrital K-feldspars that are ubiquitous in the samples. $$SiO_{2}$$ consistently is enriched in pore waters and is traceable to dissolution of diatoms. The general conclusion is that, in the average marine clayey sediment, early diagenesis is minimal but that the composition of pore waters is a guide to incipient mineral transformations.

Potentiometric, Electrical Conductance and Self-Diffusion Measurements in Clay-Water Systems

AbstractPotentiometric measurements using commercially available cationic glass electrodes, electrical conductance and self-diffusion measurements of cations and water were made in electrolyte-free 3–5 per cent Li, Na, K, Cs, Ca and Sr bentonite-water systems and bi-ionic systems with varying ratios of K and Ca. Activation energies for conductance in the homoionic clays were calculated using the Arrhenius equation.The agreement between cation mobilities measured by diffusion and conductance indicates that the underlying mechanism is essentially the same for the two processes. But the activation energies for ion movement determined for conductance measurements do not explain the observed reduction in mobility. Only two clays, Li and Cs, gave values significantly higher than for the measured solution conductance and only the Cs clay gave a value higher than those calculated for ion conductance at infinite dilution.Increasing Ca saturation in K-Ca clays from 1 to 99 per cent increased the self-diffusion coefficient or mobility of K by a factor of about 1.7 and Ca by a factor of about 30 reflecting the effect of the predominate accumulation of the divalent cation in regions of highest negative potential. The reduction in activity of monovalent cations calculated from the potentiometric measurements, although of the same order of magnitude, was consistently less than the corresponding reduction in mobility in both the homoionic and bi-ionic clays. This difference became greater with increasing mobility of K in the bi-ionic clays.