Structural investigation of lithium iodide in liquid dimethyl sulfoxide: Comparison between experiment and computation

The overall coordination number of Li+ was found to be four, while the Li-DMSO coordination number is below four; the coordination sphere of the I− ion contains eight species (DMSO and lithium) in average and does not show any special geometrical arrangement. Ab initio calculations for clusters containing Li+ and up to six DMSO molecules have been performed with the B3LYP density functional and various basis sets. The calculations show an increase of the average ion-ligand distance from about 1.71-1.96 Å when the number of DMSO molecules in the cluster increases from 1 to 4. The corresponding Li-DMSO interaction energy decreases accordingly; additional DMSO molecules are accommodated in the second shell, in agreement with the results from diffraction experiments and the simulation.