Synthesis, crystal structure reinvestigation and chemical formula redefinition of cesium hydrogen oxalate by single crystal X-ray diffraction, IR spectroscopy, thermal and Hirshfeld surface analysis

In attempt to prepare a bimetallic polymer oxalate with Cr and Cs atoms, colorless single crystals have been isolated and identified as CsHC₂O_4, from X-ray powder diffraction which shown the compound to be isotypic with that reported previously by Kholodkovskaya (Space Group P2₁/c). On the lack of some structural data, its structure has been reinvestigated using new and more crystallographic data. Two independent C atoms and only one H atom are present in the asymmetric unit, with one Cs atom and moreover, the symmetry center is located on the center of the two kinds of CC bonds, allowing to propose the chemical formula Cs₂(C₂O₄)(H₂C₂O₄) (I).The structure consists of zigzag files of CsO₁₁ polyhedra sharing opposite faces via the C₂O₄²⁻ ions and form double layers separated by H₂C₂O₄ ligand layers, along [0 0 1] direction. The IR spectroscopy study, carried out by comparison with homologous compounds, is in agreement with XRD data. The thermal analysis ATG and DTA performed under different atmospheric conditions, showed different thermal decomposition process for this bidimensional (2D) compound. The Hirshfeld surface analysis and its corresponding 2D fingerprint plots revealed that the major contributors to the crystal packing are Cs⋯O contacts followed by O⋯C, O⋯O, and O⋯H contacts.