A revisit of the bond valence model makes it universal

2020 ◽  
Vol 22 (25) ◽  
pp. 13839-13849 ◽  
Author(s):  
Elena Levi ◽  
Doron Aurbach ◽  
Carlo Gatti

The application of Pauling's principles to any type of chemical bond can be validated using recent quantum chemistry data (bond orders), thus making them universal.

2015 ◽  
Vol 17 (38) ◽  
pp. 25014-25026 ◽  
Author(s):  
Fahri Alkan ◽  
C. Dybowski

Accurate computation of 207Pb magnetic shielding principal components is within the reach of quantum chemistry methods by employing relativistic ZORA/DFT and cluster models adapted from the bond valence model.


2014 ◽  
Vol 70 (a1) ◽  
pp. C1689-C1689
Author(s):  
Ian Brown

The properties of the chemical bond are the same as those of the electrostatic flux that links the cores of two bonded atoms via their bonding electrons. Both the bond and the flux depend only on the number of electrons that form the bond, and significantly, neither depends on how the electron density is distributed. This allows the rules of chemical bonding to be developed using classical electrostatic theory without the need to know how the electron density is distributed. The magnitude of the flux is equal to the bond order (bond valence) and hence correlates with the bond length [1]. A network of bonds is equivalent to a capacitive electric circuit which allows one to predict the bond fluxes, hence also the bond lengths. Bond angles are determined by the spherical symmetry of the flux around each atom, and the resulting bonding geometry can be predicted using little more than a pocket calculator. The rules of all the predictive bond models: the VSEPR model, the ionic model, the covalent bond model and the bond valence model can be derived using classical electrostatics without introducing problematic concepts such as hypervalency, dative bonding, hybridization and the dichotomy between ionic and covalent bonding, thus eliminating the paradoxes created by the physically questionable Lewis and orbital models. Quantum effects are rarely important except in the transition metals where in some cases they perturb the bonding geometry.


Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 304
Author(s):  
Elena Levi ◽  
Doron Aurbach ◽  
Carlo Gatti

About 70 years ago, in the framework of his theory of chemical bonding, Pauling proposed an empirical correlation between the bond valences (or effective bond orders (BOs)) and the bond lengths. Till now, this simple correlation, basic in the bond valence model (BVM), is widely used in crystal chemistry, but it was considered irrelevant for metal–metal bonds. An extensive analysis of the quantum chemistry data computed in the last years confirms very well the validity of Pauling’s correlation for both localized and delocalized interactions. This paper briefly summarizes advances in the application of the BVM for compounds with TM–TM bonds (TM = transition metal) and provides further convincing examples. In particular, the BVM model allows for very simple but precise calculations of the effective BOs of the TM–TM interactions. Based on the comparison between formal and effective BOs, we can easily describe steric and electrostatic effects. A possible influence of these effects on materials stability is discussed.


Author(s):  
А. Я. Штейфан ◽  
В. І. Сідей ◽  
І. І. Небола ◽  
І. П. Студеняк

2008 ◽  
Vol 870 (1-3) ◽  
pp. 1-9 ◽  
Author(s):  
Olga V. Sizova ◽  
Leonid V. Skripnikov ◽  
Alexander Yu. Sokolov

1999 ◽  
Vol 32 (2) ◽  
pp. 341-344 ◽  
Author(s):  
Javier González-Platas ◽  
Cristina González-Silgo ◽  
Catalina Ruiz-Pérez

VALMAP2.0 is a Microsoft-Windows-based program designed to assist material scientists in accurate structural investigations. The aim ofVALMAPis to calculate the sum of bond valences that a particular atom would have if it were placed at any arbitrary point in the crystal. By movement of this atom through all possible points, its valence-sum contour map can be displayed. Parameters of the bond-valence model are available and may be modified. The program was tested in a number of cases and two examples of applications are reported: (i) finding probable atom sites in crystal structures; (ii) displacive and order–disorder phase transition mechanisms, analysing steric effects.


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