The resulting disconnectivity graph from the P 1 threshold simulation is shown is figure , where the branches corresponding to each local energy minimum are colored by the density of the corresponding crystal structure. Apart from now including α, a difference with respect to the P 1 and P 2 1 /c results is that the lower symmetry allows more distinct local minima to be identified within the superbasins corresponding to the known polymorphs; this is particularly noticeable around δ, where 17 structures are connected to δ at lower energy barriers than the connection of the δ superbasin to those of ε, α and β. To more clearly visualise the relationships between the five polymorphs, a simplified disconnectivity graph is shown in figure , in which all structures other than the five starting structures are hidden. The lid energies at which transitions are found between the five structures are summarised in Table .