The "Ionic Strength" of a solution is a measure of the concentration of ions in that solution.
Applicable units are those of quantitykind:IonicStrength
http://en.wikipedia.org/wiki/Ionic_strength
The "Ionic Strength" of a solution is a measure of the concentration of ions in that solution.
$I = \frac{1}{2} \sum z_i^2 b_i$, where the summation is carried out over all ions with charge number $z_i$ and molality $m_i$.
http://www.iso.org/iso/catalogue_detail?csnumber=31894