Comparison of the number of structures featuring both TFSI and a metal ion near to the TFSI core structure. The blue bars show the total number of structures for each metal found in the data and the red points specify the percentage of the total number of considered structures that feature a metal ion bound to TFSI. A given metal was considered to be bound to the N-atom of the TFSI core structure if the sum of the covalent radii of the N-atom of TFSI and the relevant metal (M) plus an empirical tolerance factor (denoted f) of 1 Å was greater than the raw distance between N and M.