Talk:Ion transport number

[Untitled]

This article needs a lot more material, including a quantitative definition and descriptions of both Hittorf and moving-boundary methods. A good starting point would be to translate either the German or the Italian articles, which are each about 10 times as long as this one. Dirac66 (talk) 23:53, 27 March 2012 (UTC)

I see that the German article de:Überführungszahl is the longest of all Wp, quite longer than the Italian version.--5.2.200.163 (talk) 15:58, 9 August 2018 (UTC)

Since I wrote the above in 2012, much has been added to the German article and very little to the Italian article. Also much has been added to the English which is now longer than the Italian. So now I would agree that the German seems the best potential source for more material to translate. Dirac66 (talk) 16:34, 9 August 2018 (UTC)

Dependence

Is this quantity somehow related or dependent on ionic radius?--5.2.200.163 (talk) 09:56, 29 July 2016 (UTC)

Ion transport number is a ratio of ionic to total molar conductivity. From memory, ionic molar conductivity is inversely proportional to hydrated ionic radius. So yes, the transport number can help to measure the hydrated ionic radius, which can be quite different from the crystallographic ionic radius in the solid state. Eventually this can be mentioned in Wikipedia article, possibly in the molar conductivity article. But first, as usual, we will need to check the sources. Dirac66 (talk) 17:22, 29 July 2016 (UTC)

I have noticed the link to here from the conductivity article. These details of the two ionic radiuses and their difference are, of course, very interesting to add there. Even more interesting would be derivation of this inverse proportionality stated here. I understand that the hydrated ionic radius is calculated based on the measured values of the molar conductivity and/or ion transport number.--82.137.12.105 (talk) 22:24, 1 August 2016 (UTC)

I notice further connections to other concepts like Stokes radius, solvation shell and ionic atmosphere.--82.137.12.105 (talk) 22:46, 1 August 2016 (UTC)

I propose the insertion in article(s) of the following statement: From ion transport number or conductivity measurements data, ionic radius can be calculated for cations and anions using the concept of Stokes radius. The values of this so-calculated ionic radius can be different from the ionic radiuses in crystals due to various solvation numbers of ions.--82.137.12.211 (talk) 12:11, 3 August 2016 (UTC)

Thank you for this suggestion. I think this point belongs in the Molar conductivity article, as the hydrated ionic radius is calculated more directly from the ionic conductivity, which in turn is calculated from the ion transport number. So I have now added a paragraph based on your text at Molar conductivity#Values of molar ionic conductivity, and in this article I have just noted that transport number can be combined with total molar conductivity to calculate ionic conductivity. Dirac66 (talk) 15:27, 3 August 2016 (UTC)

Another proposal (of clarification): how does this quantity for cations and anions relate to the diffusivity of cations and anions? Somehow again by Stokes radius concept?--82.137.9.168 (talk) 21:09, 3 August 2016 (UTC)

The article on Stokes radius summarizes the relationships between many of the quantities you have mentioned. In general the Stokes radius is the hydrodynamic radius, i.e. the radius of the particle which moves with all its "luggage". So for aqueous ionic solutions it is the hydrated ionic radius. Dirac66 (talk) 01:32, 4 August 2016 (UTC)

This calculation of Stokes radius of hydrated ions seems to be generating some anomalies when applied to certain ions like hydronium.--82.137.9.13 (talk) 00:04, 5 August 2016 (UTC)

This is explained at Molar conductivity#Values of molar ionic conductivity where it is noted that the values for H⁺ (i.e.H₃O⁺) and OH^– are exceptionally high because they conduct by the Grotthuss proton-hopping mechanism. This implies that the usual Stokes radius argument is not valid, because the ion does not actually travel thru the solution. Therefore the "Stokes radius" has no meaning for these two ions. Dirac66 (talk) 01:28, 5 August 2016 (UTC)

I see it says there that details of hopping transport mechanism are still discussed but definitely involve solvation structures of Zundel and Eigen cations. I think that the exceptionally high values of conductivity for these anomalous ions were puzzling in the frame of conventional interpretation of conductivity data, thus requiring other possible factors to be considered.--82.137.13.15 (talk) 14:26, 5 August 2016 (UTC)

Applicability of methods

Are conventional measurement methods for this quantity applicable to (anomalous) ions like hydronium and hydroxide ions? What modifications to conventional methods may be required for these special cases?82.137.13.15 (talk) 14:32, 5 August 2016 (UTC)

As I understand from physical chemistry textbooks, the experimental methods are the same for these ions as for "normal" ions. The difference is that the values of ionic mobility and conductivity are higher, as explained by the Grotthuss mechanism. Dirac66 (talk) 14:59, 5 August 2016 (UTC)

Is the Grotthuss mechanism the only explanation of high or anomalous proton conductivity? What do some sources say?--82.137.8.131 (talk) 11:44, 6 August 2016 (UTC)

It is the only one I am aware of. There are different versions as to which atom moves where in what order, and they all are quite different than Grotthuss' original version 200 years ago. But the general idea is always that ions pass protons along from one to the other, rather than the whole ion diffusing. Dirac66 (talk) 22:54, 6 August 2016 (UTC)

What is in this case the significance of diffusion for anomalous ions, which are assumed not to travel through solution?--82.137.8.131 (talk) 12:41, 6 August 2016 (UTC)

I think that regular diffusion is a slower process which plays a minor role in the movement of H3O+ and OH-, provided that these ions retain their identity long enough to diffuse. Dirac66 (talk) 22:54, 6 August 2016 (UTC)

I see this aspect about diffusion for some ions and I′ll open a new section below.--5.2.200.163 (talk) 13:38, 10 August 2018 (UTC)

How about the case of hydrated or solvated electron? What are the peculiarities that may occur? Is there something similar called electron hopping?--82.137.11.20 (talk) 21:51, 9 August 2016 (UTC)

I know very little about solvated electrons. The article on them deals mostly with nitrogen-containing solvents such as ammonia and amines rather than water, but a Google search does give some hits for hydrated electrons, usually in connection with high-energy radiation chemistry.

Actually proton conduction is also different in nitrogen solvents. In liquid NH3 and nitrobenzene, H+ moves by regular diffusion and NOT by the Grotthuss mechanism (ref. Laidler + Meiser p.282). I plan to insert this point into the Electrical mobility article soon. I have now inserted this point into the Molar conductivity article. Dirac66 (talk) 02:26, 10 August 2016 (UTC)

Also we do have an article on Solvated electrons, mostly in liquid ammonia. And one on Electron mobility in solid metals and semiconductors. Dirac66 (talk) 02:08, 11 August 2016 (UTC)

This aspect you mention here about proton is very interesting. Could you add more details from that source? I think that another very interesting aspect is the issue of ratio of weights of two mechanisms (regular diffusion and Grothus) for proton and the distinguishing or discriminating criteria (which seems to be primarily the values of conductivity?)--82.137.10.175 (talk) 09:44, 10 August 2016 (UTC)

Can you access the following source about proton conduction and solvation: Modern Aspects of Electrochemistry, vol 3, chp Proton Solvation and Proton Transfer Processes in Solutions, from p.43>, ed John Bockris and Brian Evans Conway? It would be interesting to compare with the details from Keith Laidler source.--82.137.10.175 (talk) 10:32, 10 August 2016 (UTC)

Sorry, no. I do recall seeing a paper copy of Bockris' earlier book in my university library, but it is no longer in the catalog so I presume it has been discarded. Dirac66 (talk) 02:08, 11 August 2016 (UTC)

Interesting situation about the possible discarding of a classical reference book. Has it been considered somehow outdated? The presented or contained derived formulae do not expire, of course new techniques and measurements can be developed in electrochemistry and connected domains. I think a thorough check of availability would be useful to avoid possible false presumptions. Are there other possibilities, like being lost or donated? Perhaps the library inventory manager could be asked about the situation of the book. (About the dynamic IP, I'll think of a username to be attached to the changing IP instead of creating an account. I think I'm kind of lazy about logging in each time I post a comment. This attachment of a user name to IP signature should be good enough.)--82.137.13.73 (talk) 09:11, 11 August 2016 (UTC)

Registered users do not have to log in each time. When you do log in, you are given the option of remaining logged in for 30 days (unless you log out). Then each time you go to the Wikipedia site you are already logged in.

As for my library, about 5 years ago they discarded many old books to make room for new books ... and room for computers for student use. I did protest at the time but only managed to save a very few books. Dirac66 (talk) 13:07, 11 August 2016 (UTC)

Interesting this wikifeature you mention not noticed before by me. About book discarding, has it been a physical transformation into scrap paper or perhaps a donation to other libraries less equipped has been considered? How much would the mentioned book (could) cost if available on some nearby antiquarian (bouquiniste) shop dealing used books?--82.137.9.82 (talk) 17:07, 11 August 2016 (UTC)

Relation to solvation number

Is there any relation of this quantity to solvation shell number of ions?--82.137.11.20 (talk) 21:56, 9 August 2016 (UTC)

Solvation number is the number of solvent molecules around a single ion. Not the number of ions. Dirac66 (talk) 22:10, 9 August 2016 (UTC)

Of course around a single ion, I should have said it more clearly: sh number of each ion from the ion pair of the salt dissolved.--82.137.10.175 (talk) 09:58, 10 August 2016 (UTC)

It seems that solvation number is involved implictly in Born equation for calculation of the solvation energy which uses the radius of the solvated/hydrated ion as a sum of the crystal ionic radius and diameters of the number of molecules of solvent involved in the solvated ion.--5.2.200.163 (talk) 15:02, 13 August 2018 (UTC)

Lyonium hopping anomalous conductivity

It seems that in each (protolitic) solvent the Grothus mechanism is reserved for lyonium ions by lyonium-hopping generated by molecular autoionization. Foreign ions, like hydronium in solvents different than water such as liquid ammonia, have ordinary conductivity. The conductivity of mixtures of solvents is anomalous depending on the mixing ratios of the solvents. Examples may include water alcohols mixtures where the anomalous conductivity of the hydronium decreases with the increase of alcohol content in the mixtures and concentrated strong acids-water mixtures like nitric acid and sulfuric where also the anomalous conductivity is taken by hydronitronium and hydrosulfonium. Also an interesting case to analyze would be that of supercritical water with supercritical ammonia.--82.137.9.191 (talk) 18:17, 10 August 2016 (UTC)

I propose to insert these examples in Lyonium-hopping article for which a redirect should be created to Grottus mecanism.--82.137.10.189 (talk) 18:23, 10 August 2016 (UTC)

I have never seen the word lyonium before. It seems to be IUPAC jargon for what most chemists call solvated proton. As for lyonium-hopping, it seems to be a generalization of the Grotthuss mechanism to nonaqueous solvents. I don't think we need a separate article; instead I would add a section Nonaqueous solvents to the Grotthuss mechanism article. In this section we could note various possible names for the mechanism. We could include lyonium-hopping, but a Google search (with quotation marks) shows no use of this phrase so Wikipedia should not use a phrase which is not used in the scientific literature.

Also the mobility of the solvated proton does depend on the solvent. Laidler and Meiser say that in liquid ammonia the hydrogen ion has normal mobility, in contrast to the situation in water. But in ammonia the hydrogen ion means NH₄⁺ which is the same as lyonium. Dirac66 (talk) 02:30, 11 August 2016 (UTC)

And finally I notice that your IP number is dynamic and keeps changing. To obtain a static identity on Wikipedia, you can register a permanent username as explained at Wikipedia:Why create an account? Dirac66 (talk) 02:30, 11 August 2016 (UTC)

Lyonium can include also the case of non-protic solvents. Of course a section about non-aqueous solvents could be added in the mentioned article. About the term lyonium hopping, it can't be certainly excluded (from being at least a redirect) based on the search of just online sources, it can lurk in some journals articles whose full text is not generally freely available on the net. The term is a natural combination of words which can't be avoided, there is no need to avoid it, not every possible combination of words used in Wikipedia articles need to be detected in sources in order to be used. I think in this situation falling into exaggeration can be avoided by using WP:IAR if really needed.--82.137.13.73 (talk) 09:36, 11 August 2016 (UTC)

The section about non-aqueous solvents can include the very interesting case of solvent mixtures and dependence of a particular ion hopping (another natural combination of words which need not be detected in sources before using it) on the mixing ratio of aqueous and non-aqueous protic and aprotic solvents.--82.137.13.73 (talk) 09:46, 11 August 2016 (UTC)

Of course for the situation of solvents mixtures, numerical data for journal article and secondary sources like CRC could be used as examples (in tables) and even separate Wikipedia data pages articles be created.--82.137.13.73 (talk) 09:53, 11 August 2016 (UTC)

Relation to activity coefficient

What is the connection between this quantity and the activity coefficient of ions in a transport concentration cell?--82.137.14.32 (talk) 20:53, 16 August 2016 (UTC)

Something like : $E_{T}=-2{\frac {RT}{zF}}\int \!t_{c}dln(a_{c})$ for the electromotive force E_T of the transport cell with cation c having transport number t_c?--82.137.14.32 (talk) 21:23, 16 August 2016 (UTC)

It seems that a possible relation between these quantities is of the type encountered in Darken's equations.--82.137.15.76 (talk) 11:09, 21 November 2017 (UTC)

Concentration cells involvement

Are somehow concentration cells, without or with transport, involved in the described (Hittorf, MBM) methods for obtaining numerical values of this quantity? I think it should be clearly underlined if so.--82.137.11.110 (talk) 00:23, 11 November 2017 (UTC)

Reference source : Harned and Owen Physical Chemistry of Electrolytic Solutions 1958

I have seen some sources mentioning the book Physical Chemistry of Electrolytic Solutions (1958) by H. S. Harned and B. B. Owen in re to the subject of this article. One aspect mention the comparison of the transport numbers of some ion (hydronium) by different methods (p. 482). Also other pages are mentioned: 438, 486.

I think that this book is a valuable reference source for this wikiarticle.--5.2.200.163 (talk) 13:28, 10 August 2018 (UTC)

Diffusivity determinations in the case of some ions

Given the aspect mentioned above above the rather unclear significance of diffusion process for ions like hydronium, I open this section here.--5.2.200.163 (talk) 13:41, 10 August 2018 (UTC)

Does the mentioned aspect imply that for the mentioned type of ions involving Grotthuss mechanism, diffusivities determined from conductivities and ion transport numbers using the Nernst Einstein relation is not very meaningful?--5.2.200.163 (talk) 13:47, 10 August 2018 (UTC)

Solvation number determination

I see in metal ions in aqueous solution that the ion transport numbers are used for the determination of hydration number in the solvation shell of ions.Some details could be added.--109.166.139.12 (talk) 12:28, 19 November 2019 (UTC)

In mixed solvents systems

I think that ion transport number data should be presented also for mixed solvents systems.--109.166.138.49 (talk) 21:00, 14 December 2019 (UTC)

Good idea, if someone can find the information. Dirac66 (talk) 22:17, 14 December 2019 (UTC)

Google search seems to indicate some results for these systems, as well as for the systems of molten salts and ionic liquids mentioned below. Perhaps a list of articles should be presented here before the insertion of data in article.--109.166.138.49 (talk) 20:08, 16 December 2019 (UTC)

In molten salts and ionic liquids

I think that ion transport number data should be presented also for molten salts and ionic liquids systems.-- 109.166.138.49 (talk) 21:05, 14 December 2019 (UTC)

Also a good idea, again if someone can find the information. Dirac66 (talk) 22:17, 14 December 2019 (UTC)

A list of article with results from Google search could be enumerated here for discussion of data extraction.--109.166.138.49 (talk) 20:11, 16 December 2019 (UTC)