Then the total number, 𝑛 of unique structures is calculated as: The histogram will show the frequency of every pair distance that exists in the pore, Figure is an example of the 𝑇 𝑒𝑡 2 𝐷𝑖 4 histogram. The sum of the frequencies of the whole histogram equals the number of FG-FG pairs, and the number of FG-FG pairs is equal to: