scholarly journals Metal centre effects on HNO binding in porphyrins and the electronic origin: metal's electronic configuration, position in the periodic table, and oxidation state

2012 ◽  
Vol 48 (32) ◽  
pp. 3842 ◽  
Author(s):  
Liu Yang ◽  
Weihai Fang ◽  
Yong Zhang
Keyword(s):  
Oxidation State ◽  
Periodic Table ◽  
Electronic Configuration ◽  
Metal Centre ◽  
Centre Effects

The Lithium Group

2010 ◽  
Author(s):  
George K. Schweitzer ◽  
Lester L. Pesterfield
Keyword(s):  
Charge Density ◽  
Quantum Number ◽  
Oxidation State ◽  
Periodic Table ◽  
Alkali Metals ◽  
Principal Quantum Number ◽  
Horizontal Line ◽  
Outer Electron ◽  
Aqueous Chemistry ◽  
Figure Legend

The elements which constitute Group 1 of the Periodic Table are known as the alkali metals. They are lithium Li, sodium Na, potassium K, rubidium Rb, cesium Cs, and francium Fr. (Sometimes the NH4+ ion is included among these since it resembles K+ or Rb+ in many of its reactions.) All six of the elements have atoms characterized by an outer electron structure of ns1 with n representing the principal quantum number. The elements exhibit marked resemblances to each other with Li deviating the most. This deviation is assignable to the small size of Li which causes the positive charge of Li+ to be concentrated, that is, the charge density is high. All of the elements exhibit oxidation numbers of 0 and I, with exceptions being rare, such that their chemistries are dominated by the oxidation state I. The six metals are exceptionally reactive, being strong reductants, reacting with HOH at all pH values to give H2 and M+, and having hydroxides MOH which are strong and soluble. Ionic sizes in pm for the members of the group are as follows: Li (76), Na (102), K (139), Rb (152), Cs (167), and Fr (180). The E° values for the M+/M couples are as follows: Li (−3.04 v), Na (−2.71 v), K (−2.93 v), Rb (−2.92 v), Cs (−2.92 v), and Fr (about −3.03 v). a. E–pH diagram. The E–pH diagram for 10−1.0 M Li is presented in Figure 5.1. The figure legend provides an equation for the line that separates Li+ and Li. The horizontal line appears at an E value of −3.10 v. Considerably above the Li+/Li line, the HOH ≡ H+/H2 line appears, which indicates that Li metal is unstable in HOH, reacting with it to produce H2 and Li+. Note further that Li+ dominates the diagram reflecting that the aqueous chemistry of Li is largely that of the ion Li+.

A structurally-characterized NbCl5–NHC adduct

2014 ◽  
Vol 50 (34) ◽  
pp. 4472-4474 ◽  
Author(s):  
Marco Bortoluzzi ◽  
Eleonora Ferretti ◽  
Fabio Marchetti ◽  
Guido Pampaloni ◽  
Stefano Zacchini
Keyword(s):  
Transition Metal ◽  
Oxidation State ◽  
Metal Halide ◽  
Metal Centre ◽  
X Ray

The X-ray structure of 2a is the first one reported for a monodentate NHC–niobium compound and bears the highest oxidation state ever found for a metal centre in a transition metal halide–NHC adduct.

scholarly journals THE KNIGHT S MOVE IN THE PERIODIC TABLE: a regularity amongst the d10 metals on the lower right-hand side

1993 ◽  
Vol 1 (1) ◽  
pp. 33-59
Author(s):  
Michael Laing
Keyword(s):  
Periodic Table ◽  
Electronic Configuration ◽  
Metallic State ◽  
Right Hand

This article describes a pattern of reactivity and properties of the d10 metals in the bottom right-hand side of the periodic table. Pairs of metals such as Zn-Sn, Cu-In, Ag-Tl, Cd-Pb, and Sn-Po, all related by the knight s move, are discussed, taking into consideration their properties, electronic configuration, and metallic state.

scholarly journals Periodic table from the Baruton perspective: Some anomalies and spin correlation effect

2021 ◽  
Author(s):  
Ali Bayri ◽  
fatih bulut ◽  
Serdar Altin
Keyword(s):  
Periodic Table ◽  
Spin Correlation ◽  
Electronic Configuration ◽  
Correlation Effect ◽  
Point Of View ◽  
The Other ◽  
Hartree Fock ◽  
Hund’S Rule ◽  
Total Energies ◽  
Madelung Rule

In this study, we have looked the periodic table from the Barut’s point of view and discussed the deviations from the Madelung rule. Expected, observed and computed total energies (Hartree-Fock and Gaussian) are given for two different (one for expected and the other one is observed) configurations of the Cr atom. The data shows that preferred electronic configuration for the Cr is 4s13d5 not 4s23d4 as dictated by the Madelung rule. This event may be due to the spin correlation effect which is closely related to the Hund’s rule.

scholarly journals Using Collective Knowledge to Assign Oxidation States

2020 ◽  
Author(s):  
Kevin Maik Jablonka ◽  
Daniele Ongari ◽  
Seyed Mohamad Moosavi ◽  
Berend Smit
Keyword(s):  
Machine Learning ◽  
Oxidation State ◽  
Learning Algorithm ◽  
Oxidation States ◽  
Data Driven ◽  
Chemical Formula ◽  
Collective Knowledge ◽  
Metal Centre ◽  
Data Driven Approach ◽  
Metal Organic

<div><div><div><p>Knowledge of the oxidation state of a metal centre in a material is essential to understand its properties. Chemists have developed several theories to predict the oxidation state on the basis of the chemical formula. These methods are quite successful for simple compounds but often fail to describe the oxidation states of more complex systems, such as metal-organic frameworks. In this work, we present a data-driven approach to automatically assign oxidation states, using a machine learning algorithm trained on the assignments by chemists encoded in the chemical names in the Cambridge Crystallographic Database. Our approach only considers the immediate local chemical environment around a metal centre and, in this way, is robust to most of the experimental uncertainties in these structures (like incorrect protonation or unbound solvents). We find such excellent accuracy (> 98 %) in our predictions that we can use our method to identify a large number of incorrect assignments in the database. The predictions of our model follow chemical intuition, without explicitly having taught the model those heuristics. This work nicely illustrates how powerful the collective knowledge of chemists actually is. Machine learning can harvest this knowledge and convert it into a useful tool for chemists.</p></div></div></div>

scholarly journals Using Collective Knowledge to Assign Oxidation States

2020 ◽  
Author(s):  
Kevin Maik Jablonka ◽  
Daniele Ongari ◽  
Seyed Mohamad Moosavi ◽  
Berend Smit
Keyword(s):  
Machine Learning ◽  
Oxidation State ◽  
Learning Algorithm ◽  
Oxidation States ◽  
Data Driven ◽  
Chemical Formula ◽  
Collective Knowledge ◽  
Metal Centre ◽  
Data Driven Approach ◽  
Metal Organic

<div><div><div><p>Knowledge of the oxidation state of a metal centre in a material is essential to understand its properties. Chemists have developed several theories to predict the oxidation state on the basis of the chemical formula. These methods are quite successful for simple compounds but often fail to describe the oxidation states of more complex systems, such as metal-organic frameworks. In this work, we present a data-driven approach to automatically assign oxidation states, using a machine learning algorithm trained on the assignments by chemists encoded in the chemical names in the Cambridge Crystallographic Database. Our approach only considers the immediate local chemical environment around a metal centre and, in this way, is robust to most of the experimental uncertainties in these structures (like incorrect protonation or unbound solvents). We find such excellent accuracy (> 98 %) in our predictions that we can use our method to identify a large number of incorrect assignments in the database. The predictions of our model follow chemical intuition, without explicitly having taught the model those heuristics. This work nicely illustrates how powerful the collective knowledge of chemists actually is. Machine learning can harvest this knowledge and convert it into a useful tool for chemists.</p></div></div></div>

scholarly journals Biological effects of high-diluted substances and periodic table of elements

2021 ◽  
Vol 11 (40) ◽  
pp. 192-193
Author(s):  
Cloe Taddei-Ferretti
Keyword(s):  
Periodic Table ◽  
Biological Effects ◽  
Electronic Configuration ◽  
Atomic Weight ◽  
Biochemical Basis ◽  
Loss Of Righting Reflex ◽  
Righting Reflex ◽  
Dilution Effects ◽  
And Control ◽  
Physical And Chemical

Background and Aims. There are several experimental evidences for the effects of high-diluted substances (see e.g. C. Taddei-Ferretti, A. Cotugno 1997, on effects of high-diluted drugs on the prevention and control of mice teratogenicity induced by purine derivatives; N.C. Sukul, C. Taddei-Ferretti, S.P. Sinha Babu, A. De, B. Nandi, A. Sukul, R. Dutta-Nag 2000, on high-diluted Nux vomica countering alcohol-induced loss of righting reflex in toads). Also the physical characterization and mechanism of action of high-diluted drugs have been studied (see e.g. N.C. Sukul, A. Sukul, High dilution effects: Physical and biochemical basis 2004). However, further experimental researches are needed to clarify how physical characteristics of a drug are linked to its global biological effects. Considerations on some high-diluted mineral remedies will be developer here. Methods. In Organon, sect. 119, S. Hahnemann writes: «As certainly each species of plants is different from every other one with regard to external appearance, way of life and growth, taste and smell, and as certainly each mineral, each salt is different from the others with regard to external, internal, physical and chemical qualities [...], so certainly all these vegetal and mineral substances have pathogenetic – and thus also curative – effects different among themselves [...]». This statement may be taken as basis for considering the characteristics of some elements, as ordered in the periodic table, in relation to those of some high-diluted mineral remedies. Conclusions. The elements were previously ordered in the periodic table according to the atomic weight chemically determined, and later more precisely according to the atomic number (number of protons). Then also the electronic configuration was taken into account: properties depending on atomic mass and deep electrons are not periodical, while chemical and several physical properties are linked to external electrons which have periodical configuration. In particular, let us consider the group of elements C, P, S, Cl and the group of elements Ca, Mg, K, Na. One may conclude that the four elements of the first group (respectively receiver-or-donor of 4 electrons, receiver of 3, of 2, of 1 electron), which, according to H. Bernard, are linked to the fixed human constitutions, are close among themselves in the periodic table, while they are very distant from the four elements of the second group (respectively donor of 2, of 2, of 1, of 1 electron), which are close among themselves and are linked to the changing constitutional stages.

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