An experimental electron density study of NaHC2O4.H2O at 120 K

Delaplané, R. G.; Tellgren, R.; Olovsson, Ivar

doi:10.1107/s0108768190000441

Cited by 13 publications

(2 citation statements)

References 23 publications

(29 reference statements)

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“…The comparison of the oxamato ED with that of the oxalato group in NaHC 2 O 4 ·H 2 O and of oxalic acid shows the strong influence of the metal coordination. The static deformation density of the central C−C bond in oxalic acid (0.65 eÅ -3 ) is similar to the oxamato C1−C2 bond, with a longer bond length (1.5432(4) Å versus 1.535(2) Å).…”

Section: Resultsmentioning

confidence: 94%

Electron Density Distribution of an Oxamato Bridged Mn(II)−Cu(II) Bimetallic Chain and Correlation to Magnetic Properties

et al. 2004

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The electron density distribution of the ferrimagnetic MnCu(pba)(H2O)3.2H2O chain compound, where pba stands for 1,3-propylenebis(oxamato), has been derived from high resolution X-ray diffraction measurements at 114 K using a multipolar model. The analysis of the chemical bonding has been carried out through the "Atoms in Molecules" formalism and thoroughly interpreted with regards to the strong intrachain and weak interchain magnetic couplings. The topological properties of the electron density on the oxamato bridge indicate large electron delocalization and conjugation effects, in addition to high charge transfer from both metals to the bridge. The resulting positive charges on Mn (+1.45 e) and Cu (+1.56 e) induce charge polarization of the bridge, leading to a shift of electron density from the central C atoms to the metal coordinating O and N atoms. The Mn-bridge interactions are mainly closed-shell interactions with low electron density at the corresponding bond critical points, whereas the Cu-bridge interactions exhibit significant covalent character. The Cu-N bonds are moreover stronger than the Cu-O bonds. The 3d Cu and Mn orbital populations are consistent with pyramidal and regular octahedral environments, respectively, in agreement with the loss of degeneracy due to ligand field effects. Interchain interaction pathways are evidenced by the existence of four bond critical points in hydrogen bond regions. Finally, these intrachain and interchain bonding features are correlated to the results of experimental and theoretical spin density distributions, as well as magnetic measurements.

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Section: Resultsmentioning

confidence: 94%

Electron Density Distribution of an Oxamato Bridged Mn(II)−Cu(II) Bimetallic Chain and Correlation to Magnetic Properties

et al. 2004

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“…A recent example of work in this project is the determination of the electron density in NaHC20, H,O at 120K, using X-ray and neutron diffraction techniques [35]. This is one of a limited number of investigations at low temperatures of the effect of the crystalline field on the charge density of the water molecule (see Fig.…”

Section: Structure and Dynamics In Hydrogeneous Substancesmentioning

confidence: 99%

Physics and chemistry of materials from neutron diffraction and spectroscopy

Dahlborg

Lovesey

1991

Phys. Scr.

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A short introduction to the powerful techniques of neutron diffraction and spectroscopy is illustrated largely with achievements by Swedish researchers in the past few years. Background material on sources and instrumentation is included, together with a directory of facilities routinely available to the Swedish scientific community. 1. Prologue Scattering experiments are important in many branches of chemistry and physics research. In condensed matter and materials research the projectiles used include atomic ions, electrons, neutrons and photons. While some experiments, like laser spectroscopy and x-ray diffraction, require a modest financial outlay, most demand access to major experimental facilities. The construction and operational costs are such that there is a trend toward central domestic and multinational facilities, e.g. within Europe there is the neutron reactor source at the lnstitut Laue-Langevin, and the European Synchrotron Radiation Facility under construction next door to the ILL in Grenoble. Multinational facilities are often particularly well-funded and provide advanced instrumentation, but over-demand frequently forces discrimination against timeconsuming complex experiments and training exercises. These are two of the major reasons why, more modest, domestic facilities like the R2 reactor at Studsvik are essential. Another is that optimal use of multinational facilities is only possible initial feasibility studies. Very often the information obtainable from a neutron scattering experiment is not available from other experimental techniques. The host of valuable and unique features of the neutron scattering technique vindicate the cost of building and operating neutron beam facilities. Neutron diffraction studies of crystals and disordered systems provide structural information which complements x-ray results since, for non-magnetic materials, neutrons scatter predominantly from nuclei. The strength of this scattering varies quite strongly from one isotope to isotope, in an almost random manner, so contrast studies using isotopic substitution are widely used and particularly with hydrogenous materials. Magnetic diffraction provides information on both the configuration and distribution of the magnetization density. Neutron spectroscopy is widely used for the determination of; (a) dispersion curves of collective excitations in crystals (phonons), liquids and magnetic materials (spin waves); (b) localized, non-dispersive excitations such as hydrogen vibrational states in hydrides and macromolecules and atomic and crystal field states in magnetic materials; (c) diffusion of protons and (d) proton motions in of linear reponse theory that underpins the interpretation of neutron scattering (excluding events that involve compound nuclear resonance states). The high intensity of photon beams from synchrotron sources makes it feasible to exploit magnetic photon scattering (a relativistic correction to the Thompson amplitude) as a probe of condensed matter [5]. This technique has some advantages with re...

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Structure Correlation and Ligand/Receptor Interactions

Klebe¹

1994

Structure Correlation

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An experimental electron density study of NaHC₂O₄.H₂O at 120 K

Cited by 13 publications

References 23 publications

Electron Density Distribution of an Oxamato Bridged Mn(II)−Cu(II) Bimetallic Chain and Correlation to Magnetic Properties

Electron Density Distribution of an Oxamato Bridged Mn(II)−Cu(II) Bimetallic Chain and Correlation to Magnetic Properties

Physics and chemistry of materials from neutron diffraction and spectroscopy

Structure Correlation and Ligand/Receptor Interactions

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