Table 2. -stacking interactions within (I).
| Interaction | Cg Cg () | Cgperp () |
|---|---|---|
| Cg1Cg1i | 3.6206(13) | 3.4373(9) |
| Cg2Cg2i | 3.6206(13) | 3.3627(9) |
Cg1 is the centroid of the 3,5-dicarboxybenzoate ring, Cg2 is the centroid of the 4-hydroxypyridinium ring [symmetry code: (i) x, y, 1+z], Cg Cg is the centroid-to-centroid distance, and Cgperp is the distance to the plane perpendicular to the ring centroid.