In the linear, column-bound configuration, the geometry is such that there would be an uncapped metal site. These sites can cause increased water uptake , and therefore would generally want to be avoided. This motif has a different loading value. Amine loading is typically measured as the ratio of number of amines to the number of linkers. This value can be readily measured experimentally via NMR . In the case of m2m, the loading is 2 diamines per linker. For norspermine, in the known configuration, the ratio is 1 tetramine per linker. The ratio holds for the linear, diagonally bound motif. It also holds for the column-bound S-shaped motif. For the columnbound linear motif, however, one would measure a loading of 2/3 (6 amines per 9 linkers, see image). Using this loading as the predicted value for amine screening would have you underestimate the capacity by about 33%, using the theoretical capacity of 2 CO 2 molecules per tetramine.