Steric activity of the central atom free valence electron pairs in free hexafluorobromate(1-) and hexafluoroiodate(1-) ions

1989 ◽  
Vol 28 (17) ◽  
pp. 3275-3277 ◽  
Author(s):  
Karl O. Christe ◽  
William W. Wilson
Keyword(s):  
Valence Electron ◽  
Central Atom ◽  
Free Valence ◽  
Electron Pairs

On the Structure of the [XeOF5]- Anion and of Heptacoordinated Complex Fluorides Containing One or Two Highly Repulsive Ligands or Sterically Active Free Valence Electron Pairs

1995 ◽  
Vol 34 (7) ◽  
pp. 1868-1874 ◽  
Author(s):  
Karl O. Christe ◽  
David A. Dixon ◽  
Jeremy C. P. Sanders ◽  
Gary J. Schrobilgen ◽  
Scott S. Tsai ◽  
...  
Keyword(s):  
Valence Electron ◽  
Free Valence ◽  
Electron Pairs ◽  
Complex Fluorides

Theoretical Calculation of the Polytypism Transition Temperature of Titanium Alloys on the Valence Electron Level

2012 ◽  
Vol 152-154 ◽  
pp. 342-347
Author(s):  
Hua Qu ◽  
Wei Dong Liu
Keyword(s):  
Transition Temperature ◽  
Titanium Alloys ◽  
Valence Electron ◽  
Pure Titanium ◽  
Electron Theory ◽  
Electron Level ◽  
Valence Electron Structure ◽  
Electron Pairs ◽  
Stable Element ◽  
Empirical Electron Theory

Based on the polytypism transition temperature(PPT) of pure titanium, the the empirical electron theory of solids and molecules(EET) and the basic theory of the phase transformation of titanium alloys, a new method to calculate the PTT of titanium alloys is put forward after calculating the valence electron structure(VES) parameter nA which is the covalence electron pairs on the strongest bond of alloy phases, the crystal cell weight of  and  phases in the structure, the compensation coefficient of the phase and the temperature coefficient of  stable element. After calculating the PTT of some common titanium alloys, we find that the theoretical values are consistent with the experimental ones, so it is feasible to calculate the polytypism transition temperature of the titanium alloys on the covalence electron level.

Influence of Micro-Addition Chromium on the Valence Electron Structure and Toughness of Fe2B Phase

2010 ◽  
Vol 34-35 ◽  
pp. 1135-1139
Author(s):  
Rui Na Ma ◽  
Yong Zhe Fan ◽  
Xiao Ming Cao ◽  
Ming Wen
Keyword(s):  
Fracture Toughness ◽  
Valence Electron ◽  
Chromium Content ◽  
Electron Structure ◽  
Valence Electron Structure ◽  
Electron Pairs ◽  
Good Corrosion Resistance ◽  
Length Difference ◽  
Fe2b Phase ◽  
Good Agreement

Fe2B is a kind of typical intermetallic compound, which has good corrosion resistance in molten zinc. However, the fatal intrinsic brittleness limits its further application in the Hot-Dip Galvanizing Industry. Therefore, it is worthwhile to improve the toughness of Fe2B phase. In this study, the fracture toughness property of Fe2B phase with and without micro-addition chromium is investigated. In comparison with pure Fe2B phase, the intrinsic brittleness of Fe2B phase with chromium is lower. In addition, the valence electron structure of Fe2B containing various chromium content is calculated by the method of bond length difference (BLD). The results show that, in the (Fe1-x Crx)2B phase, the number of covalent electron pairs and the weaker bond energy are increased by the substituting atom-Cr. The calculated results are in good agreement with experimental observations.

The role of non-bonding electron pairs in the asymmetric coordination environments of 1,1-dithiolate complexes

1976 ◽  
Vol 29 (11) ◽  
pp. 2541 ◽  
Author(s):  
BF Hoskins ◽  
CD Pannan
Keyword(s):  
Electron Pair ◽  
Central Atom ◽  
Main Group ◽  
Valence Shell ◽  
Electron Pairs ◽  
Shell Electron ◽  
Dithiolate Complexes ◽  
Asymmetric Coordination ◽  
Bonding Electron

Various forms of asymmetry in the lengths of the bond between the central atom and sulphur, found in differing coordination environments of 1,1-dithiolate compounds involving main group atoms, have been successfully rationalized by considering both the valence shell electron pair repulsion theory and the effect of the restricted ligand bite distance.

Free Valence Electron Centralization Strategy for Preparing Ultrastable Nanoclusters and Their Catalytic Application

2019 ◽  
Vol 58 (16) ◽  
pp. 11000-11009 ◽  
Author(s):  
Xi Kang ◽  
Hadi Abroshan ◽  
Shuxin Wang ◽  
Manzhou Zhu
Keyword(s):  
Valence Electron ◽  
Free Valence ◽  
Catalytic Application

The duodecet rule: Part 3. Fluoro species of the third period elements

1992 ◽  
Vol 70 (6) ◽  
pp. 1696-1705 ◽  
Author(s):  
E. A. Robinson
Keyword(s):  
Bond Length ◽  
Molecular Species ◽  
Central Atom ◽  
Covalent Radius ◽  
Valence Shell ◽  
Single Bond ◽  
Electron Pairs ◽  
Bond Lengths ◽  
The Third

On the basis of the suggested new value of 54 pm for the single bond covalent radius of fluorine, the previously established duodecetrule for period 3 elements in molecular species with highly electronegative ligands is extended to fluorides. It is shown, for species such as SiF4, (F3Si)2O, F3SiNH2, F3PO, and PF5, that the observed bond lengths are consistent with significant partial double bonding involving all the ligands, including fluorine, and with a total of six electron pairs in the valence shell of the central atom. Empirical rules based on d/d1, the ratio of an observed bond length to the corresponding single bond length calculated from the sum of covalent radii, are developed as a simple approximate guide to the extent of partial double bonding in bonds to third period elements. It is also shown that bond lengths in species such as Al2F5, AlO45−, and Al(NH2)4− are consistent with a duodecet rule.

ELECTRON CORRELATION AND MOLECULAR SHAPE

1960 ◽  
Vol 38 (6) ◽  
pp. 818-826 ◽  
Author(s):  
R. J. Gillespie
Keyword(s):  
Electron Correlation ◽  
Polyatomic Molecule ◽  
Central Atom ◽  
Molecular Shape ◽  
Electron Pairs ◽  
Bond Lengths ◽  
Inverse Square Law ◽  
Lone Pairs ◽  
Electrostatic Repulsions

It is proposed that the arrangements of the electron pairs in the valency shell of a central atom of a polyatomic molecule can be predicted by considering the equilibrium arrangements of similar particles on the surface of a sphere with an appropriate law of force between the particles. The arrangements resulting from an inverse square law of force, corresponding to electrostatic repulsions, and a force which is proportional to 1/rn where n is large, corresponding to Pauli forces, are considered specifically. It is shown that the arrangements predicted agree with those found experimentally for molecules containing only non-transitional elements. The possible arrangements for seven, eight, and nine pairs of electrons in a valency shell are discussed in detail. A method is suggested for predicting the arrangements of electron pairs in valency shells containing lone pairs which can occupy alternative non-equivalent positions. The effect of the interactions of electron pairs on bond lengths in certain molecules is discussed. The extension of the same principles to molecules containing transitional elements is briefly outlined.

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