X-Ray-neutron diffraction study of the electron-density distribution in trans-tetraaminedinitronickel(II) at 9 K: transition-metal bonding and topological analysis

摘要: A quantitative description of transition-metal bonding has been obtained through combined analysis 9(1) K X-ray and 13(1) K time-of-flight neutron diffraction data. It is shown that a simple valence-orbital model too crude an approximation adequately to describe the electron-density distribution of Ni(ND 3 ) 4 (NO 2 ) 2 . To exhaust more fully information present in very-low-temperature diffraction data, more flexible was used. Quantitative measures describing complex have been achieved topological derived static model density. study effects co-ordination intermolecular interactions, comparisons were made with good-quality wavefunctions calculated for free nitrite ammonium ions. Both ligands appear co-ordinated predominantly electrostatic interactions. Contrary to previous studies 2 , the topological revealed metal–ligand interactions, besides cylindrical σ contributions, also non-cylindrical π contributions to covalent part bonding. Plots the Laplacian electron density used locate regions charge concentration charge depletion valence atoms in molecule. For all atoms, maxima valence-shell are found accord simple Lewis electron-pair concept bonded non-bonded concentrations. The study demonstrates data measured carefully at very low temperatures sufficient precision allow reliable and detailed electron-density distributions.