Description of covalent bond orders using the charge density topology

2003 ◽  
Vol 16 (2) ◽  
pp. 133-141 ◽  
Author(s):  
Siân T. Howard ◽  
Olivier Lamarche
Keyword(s):  
Charge Density ◽  
Covalent Bond ◽  
Bond Orders ◽  
Density Topology

SCI: a robust and reliable density-based descriptor to determine multiple covalent bond orders

2018 ◽  
Vol 24 (8) ◽  
Author(s):  
Ying Huang ◽  
Lianghong Liu ◽  
Chunying Rong ◽  
Tian Lu ◽  
Paul W. Ayers ◽  
...  
Keyword(s):  
Covalent Bond ◽  
Bond Orders

Covalent bond orders revisited: the open-shell case

2008 ◽  
Vol 10 (33) ◽  
pp. 5144 ◽  
Author(s):  
Diego R. Alcoba ◽  
Roberto C. Bochicchio ◽  
Luis Lain ◽  
Alicia Torre
Keyword(s):  
Covalent Bond ◽  
Open Shell ◽  
Bond Orders

Theoretical Studies of the Atomic and Electronic Structure of Mercury/Aluminium Oxide Interface

2011 ◽  
Vol 255-260 ◽  
pp. 2972-2976 ◽  
Author(s):  
Ping He ◽  
Jiang Wu ◽  
Xiu Min Jiang ◽  
Nai Chao Chen
Keyword(s):  
Charge Density ◽  
Density Functional ◽  
Covalent Bond ◽  
Partial Density ◽  
Oxide Interface ◽  
Functional Theory ◽  
Adsorption Sites ◽  
Interacting Electrons ◽  
Strong Covalent Bond ◽  
Evolution Tendency

Density-functional theory (DFT) theory is conducted for the structural and electronic features at the Hg/Al2O3 interface by the analysis of optimal structural geometry, partial density of states (PDOS) and difference charge density. The two adsorption sites of on-top and hollow locations according to the symmetry is adopted to construct the associated interfacial models between Hg atom and free surface. The calculated studies show that the oxygen atoms near Hg atom in the Al2O3 surface, for both on-top and hollow sites, have the gathering effect by shifting toward Hg atom. But their interacting electrons at the interface exhibit different statues in terms of the PDOS analysis that there have no evolution tendency to form the bond between associated O and Hg atoms at the on-top site; and the occurrence of Hg-5d and O-2p overlapping orbitals reveals the strong covalent bond existed at the interface. The PDOS curves show that Al atom in the surface is not liable to contribute to the formation of corresponding bonds by mixing its electrons with Hg atom. Meanwhile, the calculated results derived from difference charge density are in good agreement with the PDOS analysis. The calculated results support some advanced atomic investigation on design a new sorbent refined from fly gas, especially improving the mercury removal from the flue gas.

scholarly journals Experimental evidence of a 3-centre, 2-electron covalent bond character of the central O–H–O fragment on the Zundel cation in crystals of Zundel nitranilate tetrahydrate

CrystEngComm ◽  
2017 ◽  
Vol 19 (28) ◽  
pp. 3898-3901 ◽  
Author(s):  
Krešimir Molčanov ◽  
Christian Jelsch ◽  
Emmanuel Wenger ◽  
Jernej Stare ◽  
Anders Ø. Madsen ◽  
...  
Keyword(s):  
Solid State ◽  
Charge Density ◽  
Experimental Evidence ◽  
Covalent Bond ◽  
Covalent Nature ◽  
Bond Character

Charge density of the Zundel cation in the solid state reveals a covalent nature of its central O–H–O fragment.

From topology to geometry

1996 ◽  
Vol 74 (6) ◽  
pp. 1229-1235 ◽  
Author(s):  
Mark Eberhart
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Charge Density ◽  
Systematic Study ◽  
Ductile Failure ◽  
Geometrical Theory ◽  
Density Topology ◽  
Topological Theory ◽  
Metal Aluminides ◽  
B2 Structure

A systematic study of the charge density topologies corresponding to a number of transition metal aluminides with the B2 structure indicates that unstable crystal structures are sometimes associated with uncharacteristic topologies. This observation invites the speculation that the "distance" to a topological instability might relate to a metals phase behavior. Following this speculation, a metric is imposed on the topological theory of Bader, producing a geometrical theory, where it is now possible to assign a distance from a calculated charge density topology to a topological instability. For the cubic transition metals, these distances are shown to correlate with single crystal elastic constants, where the metals that are furthest from an instability are observed to be the stiffest. Key words: crystal structure, charge density topology, mechanical properties, brittle/ductile failure.

First-Principles Study on Electronic Structure of 15R-SiC Polytypes

2014 ◽  
Vol 971-973 ◽  
pp. 77-80 ◽  
Author(s):  
Fu Chun Zhang ◽  
Ying Gao ◽  
Hong Wei Cui ◽  
Xing Xiang Ruan ◽  
Wei Hu Zhang
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Charge Density ◽  
Band Gap ◽  
Density Functional ◽  
Covalent Bond ◽  
Lattice Parameter ◽  
Pseudopotential Approach ◽  
Structure Density ◽  
Indirect Band Gap

To study the geometrical and electronic structure of 15R-SiC polytypes, the lattice parameter, band structure, density of states (DOS) and charge density of 15R-SiC are calculated by using density functional theory based on the plane wave pseudopotential approach, and electronic structure and ground properties of 15R-SiC are investigated by the calculated band structure and DOS, the results show that 15R-SiC is an indirect band gap semiconductor, with calculated indirect band gap width being 2.16 eV and band gap dependent on Si 3p and C 2p states. While charge density results show that Si-C bond is a hybrid bond semiconductor strong in covalent bond and weak in ionicity, characterized by intense sp3 hybrid characteristics, which is in accordance with the experimental results. The above mentioned results are considered as theoretical reference for design and application of SiC polytype materials.

Crystal Orbital Bond Index: Covalent Bond Orders in Solids

2021 ◽  
Vol 125 (14) ◽  
pp. 7959-7970
Author(s):  
Peter C. Müller ◽  
Christina Ertural ◽  
Jan Hempelmann ◽  
Richard Dronskowski
Keyword(s):  
Covalent Bond ◽  
Bond Orders ◽  
Bond Index ◽  
Crystal Orbital

scholarly journals Bond orders for intermolecular interactions in crystals: charge transfer, ionicity and the effect on intramolecular bonds

IUCrJ ◽  
2018 ◽  
Vol 5 (5) ◽  
pp. 635-646 ◽  
Author(s):  
Khidhir Alhameedi ◽  
Amir Karton ◽  
Dylan Jayatilaka ◽  
Sajesh P. Thomas
Keyword(s):  
Charge Transfer ◽  
Intermolecular Interactions ◽  
Covalent Bond ◽  
Halogen Bonding ◽  
Close Packing ◽  
Bond Orders ◽  
Binding Motifs ◽  
Bond Indices ◽  
Interaction Regions

The question of whether intermolecular interactions in crystals originate from localized atom...atom interactions or as a result of holistic molecule...molecule close packing is a matter of continuing debate. In this context, the newly introduced Roby–Gould bond indices are reported for intermolecular `σ-hole' interactions, such as halogen bonding and chalcogen bonding, and compared with those for hydrogen bonds. A series of 97 crystal systems exhibiting these interaction motifs obtained from the Cambridge Structural Database (CSD) has been analysed. In contrast with conventional bond-order estimations, the new method separately estimates the ionic and covalent bond indices for atom...atom and molecule...molecule bond orders, which shed light on the nature of these interactions. A consistent trend in charge transfer from halogen/chalcogen bond-acceptor to bond-donor groups has been found in these intermolecular interaction regionsviaHirshfeld atomic partitioning of the electron populations. These results, along with the `conservation of bond orders' tested in the interaction regions, establish the significant role of localized atom...atom interactions in the formation of these intermolecular binding motifs.

Determination of covalent bond orders and atomic valence indices using topological features of the experimental electron density

2007 ◽  
Vol 63 (1) ◽  
pp. 142-150 ◽  
Author(s):  
Vladimir G. Tsirelson ◽  
Ekaterina V. Bartashevich ◽  
Adam I. Stash ◽  
Vladimir A. Potemkin
Keyword(s):  
Electron Density ◽  
Reasonable Agreement ◽  
Covalent Bond ◽  
Bond Orders ◽  
Orbital Theory ◽  
Topological Features ◽  
Experimental Electron Density ◽  
Atomic Valence

We present an approach for the determination of covalent bond orders from the experimental electron density and its derivatives at the bond critical points. An application of this method to a series of organic compounds has shown that it provides a bonding quantification that is in reasonable agreement with that obtained by orbital theory. The `experimental' atomic valence indices are also defined and their significance for the characterization of chemical problems is discussed.

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