It is molecule 4 now that has the largest µ across the whole set. This originates from the high µ GM and the large energy gap between the global minimum and the second most stable structure on the predicted lattice energy landscape, leading to µ = µ max = µ GM . Molecule 5 is slightly less favourable according to µ because, despite very high µ GM and µ max , the landscape for 5 also contains many low energy crystal structures with low predicted electron mobilities (Fig. ).