Strong Cation Anion Research Articles

The effect of temperature on the stability of ion-exchange resins in aqueous medium

The effect on ion-exchange resins of the polystyrene type of a thermal treatment has been studied by heating strong cation and strong anion resins in water at 95°C and 250°C and obtaining the IR spectra of the remaining resins as well as those of the decomposition products extracted by the water. The degradation of the resins is highly dependent on their ionic form. The (OH−) and the (H+) forms are more labile, losing completely their exchange capacity at 250°C, while the (Li+) form retains considerable ion-exchange capacity. On the other hand, the hydrothermal process affects differently the backbone of the anion and the cation resins. There are similarities in the type of decomposition products found after hydrothermal treatment with those observed after radiolytic exposure of the resins. Heating the resins in water reduces the crosslinking of the polystyrene matrix.

A study of counter-ion binding to reversed micelles by nuclear magnetic quadrupole relaxation of 81Br.

Measurements of the nuclear magnetic relaxation (nmr) of 81Br in the isotropic solution phase extending from the hexanol corner in the cetyltrimethylammonium bromide/n-hexanol/water system are presented. The effect on the 81Br nuclear magnetic resonance line width of varying the resonance frequency, the temperature, and the concentrations of the components in the solution has been investigated. It is found that except for high hexanol contents the bromide ions are located in the water cores of reversed micelles. At the highest hexanol concentrations the relaxation rate is very fast. This is found to be due to ion pair formation. At high water concentrations the bromide ion binding is not affected by changing the solution composition. Lowering the water concentration in the part of the solution phase rich in cetyltrimethylammonium bromide leads to a strong cation-anion interaction. A comparison with viscosity and X-ray data demonstrates that the enforced cation-anion coupling is due to a firm binding of the anions to the micellar surface. A simple model in which the bromide ions are rapidly exchanging between two sites, provides a description of the observations. The extensive association in these solutions also is reflected in the observed apparent energies of activation of the relaxation process. These are very high compared to those observed in aqueous solutions of alkali bromides.

Chloryl compounds. Part II. Chloryl hexafluoroarsenate and chloryl fluoride

The infrared and Raman spectra of chloryl hexafluoroarsenate have been obtained. The observed vibrations have been interpreted in terms of an ionic compound ClO2+AsF6−, where strong cation–anion interaction results in a symmetry lowering of the AsF6− ion. The compound together with chloryl fluoride produces the chloronium cation ClO2+(solv) in solution of fluorosulfuric acid. The solvolysis of FClO2 is studied by conductometry and 19F nuclear magnetic resonance (n.m.r.) in order to elucidate the observed anion–cation interaction for ClO2AsF6 more fully. 19F n.m.r. studies of FClO2 and related molecules have been used to discuss the bonding in chloronium compounds.

Chromatography and zone electrophoresis of inorganic ions dissolved in fused salts : VI. The electrophoretic behaviour of some inorganic anions in alkali nitrate and perchlorate melts

The electrophoretic mobilities of some inorganic anions dissolved in molten LiNO 3 at 300°, (Li-K)NO 3 eutectic at 160°, (Na-K)NO 3 mixture of 250° and (Li-K)ClO 4 eutectic at 300° are reported and discussed. In (Li-K)ClO 4 eutectic, all the anions examined, except ClO 4 −, move towards the cathode or stay at the point of application. This is probably due to a strong cation-anion interaction, according to the Blander 11 model of molten salts, occurring between the Li ions of the solvent and the dissolved anions. From the differences between the mobilities of the chloride and bromide ions in the solvents examined, an approximate scale for the associating power of the cations of these solvents could be established.

Spectral evidence for interionic forces in crystal—chromates and dichromates

The spectra of 31 chromates, seven dichromates, and CrO 3 have been measured from 250 to 4000 cm −1 and from 13000 to 50000 cm −1. The spectra in the region from 250 to 1000 cm −1 are reported in detail. Strong cation—anion interactions in many chromates, especially those of many of the transition metals are indicated.