| for all types of ions in a solution, half the sum of the products of their molality bi and the square of their charge number zi |
Note 1 to entry: Charge number is a quantity of dimension one defined in 113-05-17.
Note 2 to entry: The coherent SI unit of ionic strength is mole per kilogram, mol/kg.
Note 3 to entry: This entry was numbered 111-15-29 in IEC 60050-111:1996. It has been modified as follows: a formula has been added.