The Gutmann-Mayer Solvent Map

The solvents are rarely innocent bystanders. They actively participate, they coordinate, they shield, and they stabilize the intermediates.

To help make sense of this, I've found it incredibly helpful to visualize solvents using two fundamental parameters derived from Gutmann and Mayer:

• The Donor Number (DN): This measures a solvent's Lewis basicity: how well it can donate an electron pair to stabilize a cation.
• The Acceptor Number (AN): This measures its Lewis acidity: how well it can accept electron density to stabilize an anion.

Why is this useful?

Plotting solvents this way gives us a practical "map" for troubleshooting reactions. For example, if you are trying to generate a highly reactive radical anion and your reaction keeps failing, checking the map might reveal your solvent has a high Acceptor Number (meaning it's binding to and quenching your anion). Conversely, if your electrolyte won't dissolve, you might need to move to the right on the Donor Number axis to find a solvent that better coordinates your metal cations.

 

I put together this interactive map based on Izutsu's data to help visualize these relationships. You can click on the bubbles or use the dropdown to explore how different solvents behave.

Interactive Solvent Properties Map

Donor Number vs. Acceptor Number. Bubble size represents relative permittivity (ε_r).

Coordinate Space

Lab Notes

Select a Solvent

Donor Number (DN) --

Acceptor Number (AN) --

Permittivity (ε_r) --

Class --

Select a solvent on the graph or from the dropdown to view its specific properties and behavioral notes.

Reference: Izutsu, K. Electrochemistry in Nonaqueous Solutions, 2nd Ed.; Wiley-VCH, 2010.

Gutmann-Mayer Solvent Data

Solvent	Formula	Donor Number (DN)	Acceptor Number (AN)	Permittivity	Class