of pore sizes, where 𝑁 represents the total number of points in the histogram and 𝑛 𝑖 the number of points associated with the 𝑖 th bin. This number bears resemblance to a statistical measure widely used in other scientific domains. In political science, it is used to measure the effective number of political parties, while in ecology, the inverse Simpson's index evaluates the species diversity in an ecosystem . Similarly, in quantum physics, the inverse participation number measures the degree of localization of a wave-function. In our case, this effective number of pore sizes gives an idea of the diversity of pore sizes (considering a binning of 0.1 Å). A large effective number suggests that multiple pore sizes are well represented in the structure. Thus, this descriptor provides insight into the scattering of pore sizes within the distribution.