On a molality basis, \[I_{m}=\frac{1}{2}\ \sum m_{\text{B}}\ z_{\text{B}}^{2}\] where the sum goes over all the ions B. \(z_{\text{B}}\) is the @C00993@ of ion B. The ionic strength on a concentration basis is defined analogously \[I_{c}=\frac{1}{2}\ \sum c_{\text{B}}\ z_{\text{B}}^{2}\]
Green Book, 2nd ed., p. 50 [Terms] [Book]
PAC, 1996, 68, 957. (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 977 [Terms] [Paper]