Electrostriction, ion solvation, and solvent release on ion pairing

Area of Science:

• Physical Chemistry
• Solution Chemistry

Background:

• Electrostriction volume is a key parameter in understanding ion-solvent interactions.
• Quantifying ion solvation and solvent release in ion pair formation is crucial for solution behavior.

Purpose of the Study:

• To develop a theoretical method for calculating mean molar electrostriction volumes of electrolytic solvents.
• To determine ion solvation numbers at infinite dilution.
• To quantify solvent molecules released during ion pair formation.

Main Methods:

• Calculated theoretical mean molar electrostriction volume of solvents (DeltaVel(solvent)) using compressibility and permittivity data.
• Defined molar electrostriction by ions (DeltaVel(ion)) as the difference between standard partial molar volumes and intrinsic volumes.
• Determined solvation number (ninfinity) as the ratio of DeltaVel(ion) to DeltaVel(solvent).
• Calculated solvent molecules released during ion pair formation (Deltanip) from the molar volume change (DeltaVip) and DeltaVel(solvent).

Main Results:

• Tabulated solvation numbers (ninfinity) for various ions in different solvents.
• Tabulated solvent release numbers (Deltanip) for ion pairs.
• The study provides a novel approach for non-aqueous solvents.

Conclusions:

• The developed method allows for the theoretical determination of ion solvation numbers and solvent release in ion pair formation.
• This approach extends the understanding of electrostriction phenomena in electrolytic solutions.
• The findings lay the groundwork for future investigations in non-aqueous solvent systems.