I want to run an experiment to test the conductivity of various ionic compounds dissolved in water. I was hoping to see some sort of trend in the increase/decrease of conductivity based on my choice of salts. Except, conceptually, I don't quite get how my choice in the different compounds would affect conductivity.


  1. I am somewhat aware of Kohlrausch's Law, but for my experiment I was not seeking to change dilution, temperature or electrode distances. What I wanted to do was to study the effect of the structure of ionic compound or charge of the ions on Conductivity.

  2. I also wanted to compare my conductivities to some literature values.


Just so this isn't a waste of time, I would like to know:

  1. Does the structure of an ionic compound or the charge of its ions affect its conductivity, given that dilution and temperature will remain constant?
  2. If so, how?
  3. Is there a reliable Databse I can compare my results with?

I'm not too fussed about which ionic compounds they are, I would just like to understand how the compound itself plays a role in conductivity so I can confirm it with my experiment?

Thank you so much,


In a solution containing a dissolved ionic compound, to what extent is the ease of mobility of electrons or conductivity affected by either the electrophoric drag (presumably of polar water) and/or by the original structure (lattice shape) & charge of both the metallic and non-metallic ions?

  • $\begingroup$ This is like textbook example of too broad question. $\endgroup$ – Mithoron May 16 '18 at 18:01
  • $\begingroup$ Sorry, let me re-phrease: When I say, "Does the structure of an ionic compound or the charge of its ions affect its conductivity in a solution, given that dilution and temperature will remain constant?" Effectively, I am asking to what extent Electrophoresis or Electron mobility is slowed by the drag of the polar liquid (water) and to what extent the mobility is affected by the charge of the separated ions within the solution. Does the charge of the ions or the original structure of the Ionic crystal have any affect on the conductance or ease of electron movement in a solution? $\endgroup$ – Z. Steam May 16 '18 at 19:21

It turns out, according to this paper, stated:

The solvent-berg model which put forward the suggestion that smaller ions are strongly interacting with the nearest neighbour shell of solvent molecules. This was considered to be particularly true of cations since these are generally smaller in size than the corresponding anions and have a higher charge density. The ion essentially carries this shell of solvent molecules long enough that this leads to a larger effective diameter which lowers its conductivity to a value smaller than the conductivity of larger ions which have no strongly attached shells of solvent.

And in terms of drag from the polarity of the solvent, namely water, they showed a formula for dielectric friction:

ζDF = 3qi20 − εD/(cri3(2ε0 + 1)ε0)


ζDF is the dielectric friction,
ri and qi are the radius and charge of the ion,
ε0 and ε are the static and high frequency dielectric constants of the solvent,
c is the product of the limiting ionic conductivity and viscosity of the solvent,

So, I assume that the ionic radius will play a role in its drag by the surrounding polar solvents which will affect its mobility, and therefore the conductance.

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