Interanionic O−H⋅⋅⋅O Interactions: The Charge Density Point of View

Local attractions characterize the interanionic O−H⋅⋅⋅O hydrogen bonds in crystalline potassium hydrogenoxalate. This is the conclusion of theoretical and experimental studies on the electron density distribution. This contradicts a recent claim that such interactions are electrostatically repulsive. The picture shows the Laplacian function of the electron density in the region of the hydrogen bond.