Combined distribution functions (CDFs) can give additional information on hydrogen bonding by monitoring both the distance and angle of specific intermolecular interactions occurring between the cations and anions. In Figure , we show a CDF, in which the X axis represents the distance from the hydrogen atom H 1 of the [EMI] + cation to nitrogen atom N 1 of the [TFSI] - anion and the Y axis depicts the angle defined by the vector which goes from the H 1 atom to the C 1 atom of the cation and the vector connecting the atom H 1 and the nitrogen N 1 of the anion. A value of this angle of 180° indicates that the atoms C 1 , H In Figures and, we analyze now the hydrogen bond interaction between the [EMI] + cation and the carbony oxygen of EC and DMC molecules. A CDF is given in Figure , in which the X axis represents the distance from the hydrogen atom H 1 of the [EMI] + cation to carbonyl oxygen atom O 3 of the EC and the Y axis depicts the angle defined by the vector which goes from the H 1 atom to the C 1 atom of the cation and the vector connecting the atom H 1 and the oxygen O 3 of EC. A value of this angle of 180° indicates that the atoms C 1 , H 1 and O 3 are aligned (the hydrogen bond would be perfectly linear). In Figure , for system F 1 , a stronge signal is visible around 300pm/145° and 500pm/10° indicating a very weak H 1 -O 3 interaction between H 1 atom of imidazolium and carbonyl oxygen of EC. For system E 1 , a weak signal is clearly visible around 200pm/25°. For system D 1 , there are no clearly visible signals indicating that the interaction between the carbonyl of EC H 1 atom of [EMI] + is very minimum. In Figure , we show a CDF, in which the X axis represents the distance from the hydrogen atom H 1 of the [EMI] + cation to carbonyl oxygen atom O 3 of DMC and the Y axis depicts the angle defined by the vector which goes from the H 1 atom to the C 1 atom of the cation and the vector connecting the atom H 1 and the carbonyl oxygen O 3 of DMC. For system F 1 , a weak signal is visible around 400pm/35° indicating a very weak H 1 -O 3 interaction between H 1 atom of imidazolium and carbonyl oxygen of DMC. For system E 1 and D 1 , there are no clearly visible signals indicating that the interaction between H 1 atom of imidazolium and carbonyl oxygen of DMC is very minimum. The hydrogen bond interactions in the [EMI][TFSI] are quite weak, as even for small concentrations of IL in carbonate.