scholarly journals The role of radial nodes of atomic orbitals for chemical bonding and the periodic table

2006 ◽  
Vol 28 (1) ◽  
pp. 320-325 ◽  
Author(s):  
Martin Kaupp
2007 ◽  
Vol 06 (01) ◽  
pp. 165-175
Author(s):  
MICHAEL J. BUCKNUM ◽  
EDUARDO A. CASTRO

A heuristic proposal is made in this communication that involves potentially unusual chemical bonding between the 3d transition series element Ni and the 3d transition series metals preceding it in the Periodic Table. The bonding in such mixed metal dimers, and their potential realizations as some simple three-dimensional (3D) extended structures in a one-to-one stoichiometry, as sphaelerite, rocksalt or CsCl structure-types, is proposed to include two principal components that involve either covalent or ionic contributions. Ordinary covalent contributions from a σ bond (or band) formed from overlap of singly occupied 4s atomic orbitals on each metal center are proposed to be operative in these molecules (or their extended realizations). However, in addition to this 4s–4s σ bond (band), an unprecedented transfer of a d electron from the incomplete, open 3d9 subshell of the transition metal involved in the bonding that precedes Ni in the Periodic Table, into the 3d9 subshell on the Ni center, which results in completion of this 3d subshell in Ni , is here implicated as a further driving force for the formation of these species. The resulting molecular and extended structures MNi , where M is a 3d transition metal preceding Ni in the Periodic Table (i.e. M = Sc , Ti , V , Cr , Mn , Fe and Co ), are therefore proposed to be bonded together by a combination of covalent and ionic forces, such that the Ni center acts as an anion of charge 1-, a so-called nickelide anion Ni -, while its counterpart is a univalent cation M +. This proposal is consistent with commonly employed electronegativity scales of chemical bonding, and with considerations of the relative orbital energies of the 3d subshells of the elements across the 3d transition series period, as well as with known trends in covalent and ionic bonding in the Periodic Table of the elements. It is also found to be in agreement with the spin multiplicities calculated in the nickel dimers MNi ( M = Sc , Ti , V , Cr , Mn , Fe and Co ) if Hund's rule is assumed to be operative.


2020 ◽  
Vol 42 (2) ◽  
pp. 18-21
Author(s):  
Juris Meija ◽  
Javier Garcia-Martinez ◽  
Jan Apotheker

AbstractIn 2019, the world celebrated the International Year of the Periodic Table of Chemical Elements (IYPT2019) and the IUPAC centenary. This happy coincidence offered a unique opportunity to reflect on the value and work that is carried out by IUPAC in a range of activities, including chemistry awareness, appreciation, and education. Although IUPAC curates the Periodic Table and oversees regular additions and changes, this icon of science belongs to the world. With this in mind, we wanted to create an opportunity for students and the general public to participate in this global celebration. The objective was to create an online global competition centered on the Periodic Table and IUPAC to raise awareness of the importance of chemistry in our daily lives, the richness of the chemical elements, and the key role of IUPAC in promoting chemistry worldwide. The Periodic Table Challenge was the result of this effort.


2016 ◽  
Vol 18 (45) ◽  
pp. 30946-30953 ◽  
Author(s):  
Damien Magne ◽  
Vincent Mauchamp ◽  
Stéphane Célérier ◽  
Patrick Chartier ◽  
Thierry Cabioc'h

The role of the surface groups in chemical bonding in two dimensional Ti3C2is evidenced at the nano-object level.


2018 ◽  
Vol 1049 ◽  
pp. 012016
Author(s):  
L S Ang ◽  
S S M Fauzi ◽  
M Umi Hanim ◽  
A Amin Zhafran ◽  
M N N Najwa-Alyani

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4227
Author(s):  
Alessandro Cossard ◽  
Silvia Casassa ◽  
Carlo Gatti ◽  
Jacques K. Desmarais ◽  
Alessandro Erba

The chemistry of f-electrons in lanthanide and actinide materials is yet to be fully rationalized. Quantum-mechanical simulations can provide useful complementary insight to that obtained from experiments. The quantum theory of atoms in molecules and crystals (QTAIMAC), through thorough topological analysis of the electron density (often complemented by that of its Laplacian) constitutes a general and robust theoretical framework to analyze chemical bonding features from a computed wave function. Here, we present the extension of the Topond module (previously limited to work in terms of s-, p- and d-type basis functions only) of the Crystal program to f- and g-type basis functions within the linear combination of atomic orbitals (LCAO) approach. This allows for an effective QTAIMAC analysis of chemical bonding of lanthanide and actinide materials. The new implemented algorithms are applied to the analysis of the spatial distribution of the electron density and its Laplacian of the cesium uranyl chloride, Cs2UO2Cl4, crystal. Discrepancies between the present theoretical description of chemical bonding and that obtained from a previously reconstructed electron density by experimental X-ray diffraction are illustrated and discussed.


2011 ◽  
Vol 1 (1) ◽  
pp. 1-5 ◽  
Author(s):  
D.C. Hoffman

AbstractThis year (2009) marks the 140th Anniversary of Mendeleev's original 1869 periodic table of the elements based on atomic weights. It also marks the 175th anniversary of his birth in Tolbosk, Siberia. The history of the development of periodic tables of the chemical elements is briefly reviewed beginning with the presentation by Dmitri Mendeleev and his associate Nikolai Menshutkin of their original 1869 table based on atomic weights. The value, as well as the sometimes negative effects, of periodic tables in guiding the discovery of new elements based on their predicted chemical properties is assessed. It is noteworthy that the element with Z=101 (mendelevium) was identified in 1955 using chemical techniques. The discoverers proposed the name mendelevium to honor the predictive power of the Mendeleev Periodic Table. Mendelevium still remains the heaviest element to have been identified first by chemical rather than nuclear or physical techniques. The question concerning whether there will be a future role for the current form of the periodic table in predicting chemical properties and aid in the identification of elements beyond those currently known is considered.


2004 ◽  
Vol 241 (10) ◽  
pp. R35-R37 ◽  
Author(s):  
R. A. Evarestov ◽  
V. P. Smirnov ◽  
I. I. Tupitsyn ◽  
D. E. Usvyat

2019 ◽  
Vol 21 (1) ◽  
pp. 53-58
Author(s):  
B.L. Oksengendler ◽  
S.E. Maksimov ◽  
S.U. Norbaev ◽  
L.Yu. Akopyan ◽  
M.V. Konoplyova ◽  
...  

The article contains a hypothesis on the dominance of chemical elements of top periods of the Periodic Table in living matter. The idea is that the elements of the third and next periods of the table, in contrast to the first two periods, have larger number of subvalent electron shells. Because of this, ionization of the k-electron shell by radiation (kosmic and terrestrial) in the heavy atoms always leads to the Auger cascade, which causes the destruction of molecular chains. This mechanism can play a role of the radiation filter in the selection of light chemical elements in living matter in addition to the mechanism of hydrolytic filter (G.R. Ivanitskii).


2021 ◽  
pp. 81-101
Author(s):  
Christopher O. Oriakhi

Chemical Bonding I: Basic Concepts examines general ideas of chemical bonding between atoms and ions and how this bonding affects the chemical properties of the elements. An overview of Lewis symbols, Lewis structures and the octet rule is presented including the role of valence electrons in ionic and covalent bonding. The energy changes that accompany ionic bond formation are also discussed with emphasis on lattice energy. The chapter covers guidelines and general procedures for writing Lewis structures or electron dot formulas for molecular compounds and polyatomic ions. The concepts and applications of resonance, formal charge and exceptions to the octet rules are presented, along with coverage of the relationship between bond polarity and electronegativity.


Sign in / Sign up

Export Citation Format

Share Document