Why are aprotic solvents unable to solvate negative ions well? Why are aprotic solvents unable to solvate negative ions well? I know that the reason is due to the absence of very positive hydrogen atoms, but then why are they able to solvate positive ions well? Shouldn't its ability to solvate both types of ions be the same? I thought there their ability to solvate ions is related to whether they are partially positively or negatively charged, but shouldn't the extent to which they are partially positively or negatively charged be the same as it depends on the relative positions of the electrons?
This can be attributed to the lewis acid/base properties of the solute/solvent. Anions (negative ions) and aprotic solvents both function as lewis bases. They 'repel' each other. However, a cation (positive ion) functions as a lewis acid and is 'attracted', resulting in greater dissolution.
How well a compound dissolves in a given solvent depends on a multitude of factors. This includes the two very important ones discusses here, polarity and lewis acid/base character.