In clay science, mesopores (Figure 3) are cavities with diameters of 2 – 50 nm within a clay sample in accord with IUPAC convention (Rouquerol et al., 1994), although in soil science mesopores are defined as between 30 – 70 μm (Soil Science Society of America, 1997). In clays, these pores are present between mineral stacks of several unit structures. The pore volume (or pore size) distribution of clays is commonly determined by gas adsorption methods (typically H₂O or N₂).
Cf., macropore, micropore