On Closed-Shell Interactions, Polar Covalences, d Shell Holes, and Direct Images of Orbitals: The Case of Cuprite

Abstract

Detailed experimental evidence is presented in supporting the previous report of the authors on the direct observation of d‐holes and Cu−Cu bonding in Cu2O (see figure). It is shown that the accuracy of X‐ray measurements of charge density is limited by the extinction effect, and that theoretical calculations of charge transfer are limited by the approximations made and the models used.

Physical and chemical properties of Cu(i) compounds with O and/or H

“…Such feature has been attributed to 3d-shell depletion and s-d hybridization of Cu + , which leads to a weak interaction between Cu cations that stabilizes the cuprite structure of Cu 2 O. [47][48][49]53 Figure 7 are the differential charge densities of cuprite Cu 2 O and cuprice CuOH. In both compounds, the major charge redistribution due to the interaction between the two disconnected bond networks (lattices) occurs around the Cu cations.…”

“…For cuprous oxide, this picture of chemical bonding agrees with the findings made in the previous theoretical studies. [47][48][49][50][51][52][53] The ELF of Cu 2 O is shown in Figure 6 (a); the scale is encoded using a color scheme in which values corresponding to a high degree of electron localization are shown in red while regions of low ELF values are shown in blue. At the Cu cation sites the ELF takes on low values, whereas spherical regions of high ELF (0.85) can be seen around the sites of O anions.…”

Orbital ordering in LaMnO3: estimates of structure factors and comparison of measurement methods

“…Our recent accurate re®nement by CBED gives F x (110) = 37.272 (AE0.009 or AE0.025%) (at 100 K) (Jiang et al, 2001) (the error analysis is obtained by averaging several measurements). Zuo et al (2000) have used the Zachariasen (1967) twobeam model to correct extinction effects in X-ray diffraction data for Cu 2 O crystals. For the strong low-order 111 and 200 re¯ections of Cu 2 O crystals, the associated error in the structure factors before extinction correction is about 10%; after extinction correction, it is about 1%, which is insuf®cient to see the changes in charge density due to bonding.…”

Concepts in Computational Spectrometry: The Quantum and Chemistry

“…Those calculations of electronic structure on a crystal inevitably involve assumptions and approximations beyond those practicable on a single small molecule, and in this case involve atomic center Cu or Cu þ with 29 or 28 electrons per center. Further discussions [40,41] of these diffraction experiments [38], which were intrinsically not a spectacular innovation but a significant improvement upon the preceding work elsewhere, contain pertinent references.…”