In the second solvation shell (Fig. 2), a broad distribution of coordination numbers ranging from 19 to 30 is obtained with the highest probability of 23.4% being observed for coordination number 24. This result emphasize that the solvation shell of Ni2+ in liquid ammonia is more flexible compared to the aqueous case [43] which shows a distribution from 10 to 16 with the highest probability being coordination number 13. Further comparison of structural properties of Ni2+ complexes in various environments are listed in Table 2.