The volume occupied by the mobile phase between the particles in the packed section of a column. It is also called the interstitial volume or the void volume of the column. In @L03578@, the interparticle volume is equal to the mobile-phase hold-up volume (\(V_{\text{M}}\)) in the ideal case, neglecting any extra-column volume. In gas @C01075@, the symbol \(V_{\text{G}}\) may be used for the interparticle volume of the column. In the ideal case, neglecting any extra-column volume, \(V_{\text{G}}\) is equal to the corrected gas hold-up volume (\(V_{\text{M}}^{\text{o}}\)). \[V_{\text{G}}=V_{\text{M}}^{\text{o}}=V_{\text{M}j}\]