Reinvestigation of a Two‐Dimensional Cu(II)–Ba(II) Heterometallic Coordination Polymer Based on <i>o</i> ‐Phthalate Ligand, Infrared Spectroscopy, Thermal Behavior, and Hirshfeld Surface Analysis

Single crystals of blue color have been synthesized by the slow evaporation method and have been identified by X‐ray powder diffraction to be the barium diaqua(o‐phthalato)cuprate(II) dihydrate compound, BaCu(H 2 O) 2 (C 8 H 4 O 4 ) 2 ·2H 2 O (I), previously studied by Biagini Cingi. The structure has been undertaken using X‐ray single‐crystal diffraction, enabling the precise determination of the structure, including the localization of all hydrogen atoms. As a result, both the chemical formula and the nomenclature have been adjusted, and the reinvestigated compound has finally been redefined as [BaCu(C 8 H 4 O 4 ) 2 (H 2 O) 4 ] n , corresponding to tetraaquadi(o‐phthalato)cuprate(II)barium(II). Infrared spectroscopy has confirmed the presence of phthalate and coordination water ligands. Thermogravimetric and differential thermal analyses, carried out under nitrogen atmosphere, have further provided, above all, evidence for the coordinating nature of all water molecules. Hirshfeld surface analysis and the corresponding 2D fingerprint plots have revealed key intermolecular interactions contributing to crystal packing stability. Enrichment ratio calculations have highlighted the preferred atom–atom contacts involved in these interactions. Finally, a void analysis has been performed to evaluate the structural compactness and predict potential mechanical properties.