title: Experimental and theoretical charge densities of a zinc-containing coordination polymer, Zn(HCOO)2(H2O)2.
abstract: We present a combined experimental and theoretical charge density study of the coordination polymer Zn(HCOO)(2)(H(2)O)(2), which serves as a nonmagnetic reference for the isostructural magnetic compounds containing 3d transition metals. The charge density has been modeled using the multipole formalism against a high-resolution single-crystal X-ray diffraction data set collected at 100 K. The theoretical model is based on periodic density functional theory calculations in the experimental geometry. To gauge the degree of systematic bias from the multipole model, the structure factors of the theoretical model were also projected into a multipole model and the two theoretical models are compared with the experimental results. All models, both experiment and theory, show that the Zn atom densities are highly spherical but show small accumulations of charge toward the negative ligands. The metal-ligand interactions are found to be primarily ionic, but there are subtle topological indications of covalent contributions to the bonds. The source function calculated at the bond critical points reveals a rather delocalized picture of the density in the bridging carboxylates, and this presumably reflects the exchange pathway in the magnetic analogues.
authors.affiliation: Center for Materials Crystallography, Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark.
authors.forename: Mads R V
authors.initials: MR
authors.lastname: Jørgensen
authors.forename: Simone
authors.initials: S
authors.lastname: Cenedese
authors.forename: Henrik F
authors.initials: HF
authors.lastname: Clausen
authors.forename: Jacob
authors.initials: J
authors.lastname: Overgaard
authors.forename: Yu-Sheng
authors.initials: YS
authors.lastname: Chen
authors.forename: Carlo
authors.initials: C
authors.lastname: Gatti
authors.forename: Bo B
authors.initials: BB
authors.lastname: Iversen
mesh_terms: D018360:Crystallography, X-Ray; D005561:Formates / Q000737:chemistry*; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011789:Quantum Theory; D014867:Water / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D005561:Formates; D009942:Organometallic Compounds; D011108:Polymers; D014867:Water; D015032:Zinc