NBO 7.0 : New vistas in localized and delocalized chemical bonding theory

2019 ◽  
Author(s):  
Eric D. Glendening ◽  
Clark R. Landis ◽  
Frank Weinhold
Keyword(s):  
Chemical Bonding ◽  
Bonding Theory

Introduction

1992 ◽  
Author(s):  
John A. Tossell ◽  
David J. Vaughan
Keyword(s):  
Crystal Structures ◽  
Chemical Bonding ◽  
Alkali Halides ◽  
Ionic Character ◽  
Ionic Radii ◽  
Ionic Model ◽  
Coordination Numbers ◽  
Bonding Theory ◽  
Distribution Of Elements ◽  
Complex Crystal

The early descriptions of chemical bonding in minerals and geological materials utilized purely ionic models. Crystals were regarded as being made up of charged atoms or ions that could be represented by spheres of a particular radius. Based on interatomic distances obtained from the early work on crystal structures, ionic radii were calculated for the alkali halides (Wasastjerna, 1923) and then for many elements of geochemical interest by Goldschmidt (1926). Modifications to these radius values by Pauling (1927), and others took account of such factors as different coordination numbers and their effects on radii. The widespread adoption of ionic models by geochemists resulted both from the simplicity and ease of application of these models and from the success of rules based upon them. Pauling’s rules (1929) enabled the complex crystal structures of mineral groups such as the silicates to be understood and to a limited extent be predicted; Goldschmidt’s rules (1937) to some degree enabled the distribution of elements between mineral phases or mineral and melt to be understood and predicted. Such rules are further discussed in later chapters. Ionic approaches have also been used more recently in attempts to simulate the structures of complex solids, a topic discussed in detail in Chapter 3. Chemical bonding theory has, of course, been an important component of geochemistry and mineralogy since their inception. Any field with a base of experimental data as broad as that of mineralogy is critically dependent upon theory to give order to the data and to suggest priorities for the accumulation of new data. Just as the bond with predominantly ionic character was the first to be quantitatively understood within solidstate science, the ionic bonding model was the first used to interpret mineral properties. Indeed, modern studies described herein indicate that structural and energetic properties of some minerals may be adequately understood using this model. However, there are numerous indications that an ionic model is inadequate to explain many mineral properties. It also appears that some properties that may be rationalized within an ionic model may also be rationalized assuming other limiting bond types.

scholarly journals A chemical link between Ge–Sb–Te and In–Sb–Te phase-change materials

2015 ◽  
Vol 3 (37) ◽  
pp. 9519-9523 ◽  
Author(s):  
Volker L. Deringer ◽  
Wei Zhang ◽  
Pascal Rausch ◽  
Riccardo Mazzarello ◽  
Richard Dronskowski ◽  
...  
Keyword(s):  
Phase Change ◽  
Data Storage ◽  
Chemical Bonding ◽  
Phase Change Materials ◽  
Bonding Theory

Chemical-bonding theory reveals a common electronic “fingerprint” in seemingly different phase-change materials for data storage.

scholarly journals Electronic structure of CO—An exercise in modern chemical bonding theory

2006 ◽  
Vol 28 (1) ◽  
pp. 117-126 ◽  
Author(s):  
Gernot Frenking ◽  
Christoph Loschen ◽  
Andreas Krapp ◽  
Stefan Fau ◽  
Steven H. Strauss
Keyword(s):  
Electronic Structure ◽  
Chemical Bonding ◽  
Bonding Theory ◽  
Modern Chemical

Editorial for PCCP themed issue “Developments in Density Functional Theory”

2016 ◽  
Vol 18 (31) ◽  
pp. 20864-20867
Author(s):  
Robert van Leeuwen ◽  
Johannes Neugebauer ◽  
Lucas Visscher ◽  
F. Matthias Bickelhaupt
Keyword(s):  
Density Functional Theory ◽  
Chemical Bonding ◽  
Material Properties ◽  
Density Functional ◽  
State Of The Art ◽  
The State ◽  
Functional Theory ◽  
Bonding Theory

This issue provides an overview of the state-of-the-art of DFT, ranging from mathematical and software developments, via topics in chemical bonding theory, to all kinds of molecular and material properties. Through this issue, we also celebrate the enormous contributions that Evert Jan Baerends has made to this field.

CRYSTALLIZATION BEHAVIOR OF MAGNESIUM SALTS: A SUMMARY OF SOME EXPERIMENTAL OBSERVATIONS

2009 ◽  
Vol 23 (31n32) ◽  
pp. 3761-3768 ◽  
Author(s):  
DONGFENG XUE ◽  
LONGJIANG ZOU ◽  
LEI WANG ◽  
XIAOXING YAN
Keyword(s):  
Crystal Growth ◽  
Single Crystal ◽  
Chemical Bonding ◽  
Crystallization Behavior ◽  
Single Crystal Growth ◽  
Magnesium Salt ◽  
Chemical Systems ◽  
Bonding Theory ◽  
Magnesium Salts ◽  
Reaction Routes

Some efficient methods have been developed to chemically prepare some magnesium salt products with multiscale morphologies such as MgCO 3·3 H 2 O and 5 Mg ( OH )2· MgSO 4·2 H 2 O whiskers, Mg 5( CO 3)4( OH )2·4 H 2 O microplates and aggregates, and Mg ( OH )2 plates and spheres. The crystallization processes of the as-prepared products were studied by designing different reaction routes and corresponding growth morphologies. In these solution chemical systems, Mg 2+ cation was found to be easily coordinated by various ligands, and can be easily transformed into various compounds with variable compositions. The current crystallization observations of some magnesium salts can be readily simulated by the chemical bonding theory of single crystal growth. These results can guide the further studies of various magnesium salts with controllable morphologies.

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