New inorganic chemistry data have been reported by N. Bouhmaida and co-authors

According to recent research from Puebla, Mexico, "The electron density, its topological features, and the electrostatic potential of tetrakis-mu-(acetylsalicylate)dicopper(II), Cu[C9H7O4](2), have been derived from an accurate high-resolution diffraction experiment at 100 K. This complex exhibits a polymeric structure involving one acetyl oxygen atom as a bridge in the solid state. Only van der Waals interactions between the polymeric chains are observed."

"The copper cation is octahedrally coordinated with five oxygen atoms of the aspirinate ligands and one adjacent Cu with short Cu center dot center dot center dot Cu contact distances in the range of 2.6054(1) angstrom.

For an accurate description of these findings, you can read the full paper at the journal Inorganic Chemistry, 2010, volume 49, number 14, pages 6443–6452.