Blanc's Law Research Articles

Mobilities of gaseous ions in CH 3NO 2H 2 and CH 3CNH 2 mixtures

Extending previous investigations by Loeb of mobilities in gaseous mixtures using his procedure except that the auxiliary field in these measurements was made equal to the advancing field thus giving absolute values of the mobilities, measurements of mobilities were made in mixtures of CH 3NO 2H2 and CH 3CNH 2. The mobilities in H 2 were 7.12 for the positive ions and 10.46 for the negative ions in cm./sec. per volt/cm. Those in CH 3NO 2 were 0.221 cm./sec. per volt/cm. for both ions and in CH 3CN they were 0.234 cm./sec. per volt/cm. for both ions. Both ion mobilities deviated from Blanc's law in CH 3NO 2 indicating the formation of complexes with the CH 3NO 2 ions somewhat greater in size than the normal ions in H 2. The molecules attached to negative ions somewhat less readily than to the positive ions but both final ions were of the same size. In CH 3CN mixtures both positive and negative ions deviated from Blanc's law, the positive ion showing more ready attachment of CH 3CN. The negative ion had consistently a higher mobility than the positive ion, a circumstance indicating a smaller ion and suggesting that the attaching molecule might not be CH 3CN but some impurity. Both ion addition products in CH 3CN are larger than the normal ion in H 2 but smaller than those in CH 3NO 2 as was to be expected.

Ionic Mobilities inCl2and inCl2-Air Mixtures

Work of early investigators and of Herbert Mayer indicates that the presence of traces of ${\mathrm{Cl}}_{2}$ reduces the mobility of the negative ion below that of the positive ion, a fact which appeared inconsistent with a theory of Condon and the writer. No investigations of mobilities of both ions in pure ${\mathrm{Cl}}_{2}$ have been reported. The possibility that the discrepancy between theory and observation in Mayer's results was caused by HCl in the ${\mathrm{Cl}}_{2}$ made a more careful investigation imperative. ${\mathrm{Cl}}_{2}$ carefully prepared and free from both HCl and ${\mathrm{H}}_{2}$O was used. It was found that the values of the mobilities in pure ${\mathrm{Cl}}_{2}$ on the new absolute standard for positive and negative ions was 0.654 and 0.510 cm/sec per volt/cm respectively. A study of mixtures of dry air and ${\mathrm{Cl}}_{2}$ showed that traces of ${\mathrm{Cl}}_{2}$ less than 0.1 percent reduce the negative mobility below that of the positive ion. The positive mobilities were little affected by the presence of ${\mathrm{Cl}}_{2}$ so that while positive ions obey Blanc's law in ${\mathrm{Cl}}_{2}$-air mixtures the negative ion shows a marked clustering effect. No disturbances due to dipole moments were observed for positive ions in ${\mathrm{Cl}}_{2}$ as is to be expected.

Recent Light on the Nature of Gaseous Ions

The nature of gaseous ions from a study of mobilities in mixtures. After a general survey of the previous status of the question of the nature of the gaseous ion, it is concluded that for pure gases the dielectric attraction of the molecules by the charged ion can account for the order of magnitude of the mobility nearly equally well on either cluster or small ion theory. Such calculations are therefore indecisive. The measurements of mobilities in mixtures use Blanc's law as a criterion for the absence of the change of the cluster ion. The results show that Blanc's law holds in some cases and not in others. The observed nature of the mobility curves in mixtures shows three types of effects. These may be interpreted as indicating absence of clustering, labile clustering, stable clustering. The nature of the deviations in different gases indicates that where marked stable clustering occurs it is a specific effect depending on the chemical nature of the gas and sign of charge on the ion. Such effects are superimposed on the dielectric attractions mentioned above. Erikson's results on aging are discussed in their bearing on this work.