A New Scale of Electronegativity Based on Electrophilicity Index

Noorizadeh, Siamak; Shakerzadeh, Ehsan

doi:10.1021/jp709877h

Cited by 60 publications

(37 citation statements)

References 66 publications

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“…Interested readers are directed to relevant reviews [221][222][223][224]. In addition, a lucid treatment by Huheey [225] and two recent publications [226,227] provide good summaries of and references to the various approaches, while two commentaries on EN scales by Pearson [228] and Allen [229], albeit now somewhat dated, give some of the flavor of past debates on the subject.…”

Section: Appendix B: Electronegativity (En)mentioning

confidence: 99%

Toward a comprehensive definition of oxidation state (IUPAC Technical Report)

Karen

McArdle

Takats

2014

Pure and Applied Chemistry

111

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A generic definition of oxidation state (OS) is formulated: "The OS of a bonded atom equals its charge after ionic approximation". In the ionic approximation, the atom that contributes more to the bonding molecular orbital (MO) becomes negative. This sign can also be estimated by comparing Allen electronegativities of the two bonded atoms, but this simplification carries an exception when the more electronegative atom is bonded as a Lewis acid. Two principal algorithms are outlined for OS determination of an atom in a compound; one based on composition, the other on topology. Both provide the same generic OS because both the ionic approximation and structural formula obey rules of stable electron configurations. A sufficiently simple empirical formula yields OS via the algorithm of direct ionic approximation (DIA) by these rules. The topological algorithm works on a Lewis formula (for a molecule) or a bond graph (for an extended solid) and has two variants. One assigns bonding electrons to more electronegative bond partners, the other sums an atom's formal charge with bond orders (or bond valences) of sign defined by the ionic approximation of each particular bond at the atom. A glossary of terms and auxiliary rules needed for determination of OS are provided, illustrated with examples, and the origins of ambiguous OS values are pointed out. An electrochemical OS is suggested with a nominal value equal to the average OS for atoms of the same element in a moiety that is charged or otherwise electrochemically relevant.

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Section: Appendix B: Electronegativity (En)mentioning

confidence: 99%

Toward a comprehensive definition of oxidation state (IUPAC Technical Report)

Karen

McArdle

Takats

2014

Pure and Applied Chemistry

111

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“…Thus, some inherent mathematical inconsistency in evaluating global hardness by finite difference approximation method is apparent. Although there are other formulae for the hardness and electronegativity when the quadratic model of Parr and Pearson is not valid 30–32, the effort of density functional quantification of electronegativity and hardness is not that successful and these two descriptors are still qualitative per se.…”

Section: The Density Functional Underpinning Of Hardness and Electronmentioning

confidence: 99%

Whether electronegativity and hardness are manifest two different descriptors of the one and the same fundamental property of atoms—A quest

Ghosh

Islam

2010

Int J of Quantum Chemistry

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ABSTRACT:In this report, we have tried to reveal that there is much conceptual commonality between the two fundamental theoretical descriptors of chemistry and physics-the electronegativity and the hardness. The physical hardness was introduced and theorized by condensed matter physicists. The chemical hardness was introduced by chemists to generalize and rationalize the HSAB principle. We have tried to establish that the physical hardness and the chemical hardness with evolution of time have converged to one and the same general principle-the hardness. We have also tried to understand the physical basis and operational significance of another very important descriptor arising out of theoretical constructs of chemistry-the electronegativity. We have relied upon the fact that, since these descriptors are not observables, there is no possibility of their quantum mechanical evaluation. These descriptors, therefore, should be and must be reified before suggesting ansatz for their evaluation. We have dwelt at length upon the effort of density functional definition and evaluation of electronegativity and hardness and discovered the inherent inner contradiction of the theory and measurement. We have also noted that a good number of scientists hold the opinion that the density functional formula of electronegativity is ϭ I and that of hardness is ϭ I, where I is the ionization potential of the chemical system. This study concludes that the two fundamental descriptors-the hardness and the electronegativity originate from the same source-the electron attracting power of the screened nucleus upon valence electrons and discovers the surprising result that if one measures hardness, the electronegativity is simultaneously measured and vice versa. We have also explored the ansatz of semiempirical evaluation of electronegativity and hardness of atomic systems involving the radius of the atoms. We have noted that the ansatz for electronegativity and hardness is the same. To justify our statement that if one measures hardness, the electronegativity is simultaneously measured and vice versa, we have used the evaluated set of hardness for 103 elements of the periodic table as a scale of electronegativity and found that such set of hardness data satisfies the sine qua non of a satisfactory scale of electronegativity. The electronegativity and the hardness are two different appearances of the one and the same fundamental property of atoms. They are different and also nondifferent. They are different in their fields of application. They are nondifferent when we discuss the basic philosophical structures of their origin and development.

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“…55,56 The value of the ionicity specifies the fraction of the ionic character of a molecular bond 57,58 where 0≤q ionicity ≤1 with q ionicity = 1 being the extreme ionic character. 59 We calculate the ionicity of the CdX molecules for the X 2 Σ + and (2) 2 Σ + states at its equilibrium distance R e .…”

Section: E Transition Dipole Moments Einstein's Coefficients and Iomentioning

confidence: 99%

Theoretical electronic structure of the cadmium monohalide molecules CdX (X = F, Cl, Br, I)

Badreddine

Korek

2017

AIP Advances

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The potential energy and dipole moment curves for the lowest electronic states in the representation 2s+1 Λ (±) of CdX (X = F, Cl, Br, I) molecules are investigated via complete active space self-consistent field (CASSCF) and multi-reference configuration interaction MRCI (single and double excitation with Davidson correction). For the bound states of CdX diatomic molecules the bond distances R e , the vibrational harmonic frequencies ω e , the rotational constants B e , the electronic energies relative to the ground state T e , and the permanent and transition dipole moments have been computed. The dissociation energy limits of the atomic levels of CdX compounds are also calculated. The transition dipole moment between the ground state X 2 Σ + and (2) 2 Σ + is investigated. Consequently, the transition dipole moment values of the upper state at its equilibrium position | µ 21 |, the emission angular frequency ω 21 , the Einstein coefficients of spontaneous and induced emissions (A 21 and B ω 21 ), the spontaneous radiative lifetime τ spon , the emission cross section σ 0 , the line strength and the emission oscillator strength f 21 are calculated along with the ionicity of the X 2 Σ + and (2)

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A New Scale of Electronegativity Based on Electrophilicity Index

Cited by 60 publications

References 66 publications

Toward a comprehensive definition of oxidation state (IUPAC Technical Report)

Toward a comprehensive definition of oxidation state (IUPAC Technical Report)

Whether electronegativity and hardness are manifest two different descriptors of the one and the same fundamental property of atoms—A quest

Theoretical electronic structure of the cadmium monohalide molecules CdX (X = F, Cl, Br, I)

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