Estimation of Electronegativity Values of Elements in Different Valence States

Li, Keyan; Xue, Dongfeng

doi:10.1021/jp062886k

Cited by 672 publications

(442 citation statements)

References 24 publications

Supporting

Mentioning

423

Contrasting

Unclassified

Order By: Relevance

“…The basicity based on average EN is attractive due to its dependence only on tabulated EN data, in this case that of Li and Xue (χ LX ) (Li and Xue 2006). One disadvantage for this method is that the χ LX values are not tabulated for actinides (atomic number >89) and hence would have to be derived where some of the necessary parameters in Equation B.8, notably the ionization energy, may not be known.…”

Section: B4 Discussionmentioning

confidence: 99%

“…(Zhao et al 2008b). Li and Xue's EN (χ LX ) (Li and Xue 2006) is tabulated up through actinium (atomic number = 89), but values for the other actinides would have to be derived as follows.…”

Section: (B7)mentioning

confidence: 99%

“…The numerical coefficients were originally obtained by plotting the effective ion potential (Z*/ r cryst ) versus the Pauling EN. Z* is itself a function of the effective principle quantum number (n*) (Li and Xue 2006), the ultimate ionization potential (electron affinity) (I z ), and the Rydberg constant (R ∞ = 13.6 eV). Procedurally, the electronegativity values, in this case those from Li and Xue (χ LX ), are taken from the literature or computed via Equation B.8.…”

Section: (B8)mentioning

confidence: 99%

“…Next, the average EN (χ av ) is computed using Equation B.7 from the number of atoms of a particular element (N i ) and the EN of the element (χ i ), where the scale of EN used (e.g. Pauling (Pauling 1932) or Li and Xue (2006)) partially determines the coefficients B and C in Equation B.9 used to compute OB (Λ χav ). The significance of coefficients B and C is discussed later in this paper.…”

Section: (B8)mentioning

confidence: 99%

See 3 more Smart Citations

Optical Basicity and Nepheline Crystallization in High Alumina Glasses

Rodriguez¹,

McCloy²,

Schweiger³

et al. 2011

View full text Add to dashboard Cite

SummaryThe purpose of this study was to find compositions that increase waste loading of high-alumina wastes beyond what is currently acceptable while avoiding crystallization of nepheline (NaAlSiO 4 ) on slow cooling. Nepheline crystallization has been shown to have a large impact on the chemical durability of high-level waste glasses. It was hypothesized that there would be some composition regions where high-alumina would not result in nepheline crystal production, compositions not currently allowed by the nepheline discriminator.Optical basicity (OB) and the nepheline discriminator (ND) are two ways of describing a given complex glass composition. This report presents the theoretical and experimental basis for these models. They are being studied together in a quadrant system as metrics to explore nepheline crystallization and chemical durability as a function of waste glass composition. These metrics were calculated for glasses with existing data and also for theoretical glasses to explore nepheline formation in Quadrant IV (passes OB metric but fails ND metric), where glasses are presumed to have good chemical durability. Several of these compositions were chosen, and glasses were made to fill poorly represented regions in Quadrant IV.To evaluate nepheline formation and chemical durability of these glasses, quantitative X-ray diffraction (XRD) analysis and the Product Consistency Test were conducted. A large amount of quantitative XRD data is collected here, both from new glasses and from glasses of previous studies that had not previously performed quantitative XRD on the phase assemblage.Appendix A critically discusses a large dataset to be considered for future quantitative studies on nepheline formation in glass. Appendix B provides a theoretical justification for choice of the oxide coefficients used to compute the OB criterion for nepheline formation.v

show abstract

Section: B4 Discussionmentioning

confidence: 99%

Section: (B7)mentioning

confidence: 99%

Section: (B8)mentioning

confidence: 99%

Section: (B8)mentioning

confidence: 99%

See 2 more Smart Citations

Optical Basicity and Nepheline Crystallization in High Alumina Glasses

Rodriguez¹,

McCloy²,

Schweiger³

et al. 2011

View full text Add to dashboard Cite

show abstract

“…According to the orbital hybridization sets we have developed, when the coordination number of a RE element is less than 10, 4f electrons do not participate in the chemical bonding. In such a case, we may use other metals to partially or completely replace RE metals under the guide of ionic electronegativity scale [9,10].…”

mentioning

confidence: 99%

4f chemistry towards rare earth materials science and engineering

Xue

Sun

2017

Sci. China Technol. Sci.

Self Cite

View full text Add to dashboard Cite

The big challenge in rare earth (RE) resource utilization is to effectively manage their balanced use and advanced applications of 17 elements (Sc, Y and La−Lu) [1,2]. As a family, RE materials possess outstanding optical, electronic, and magnetic properties owing to the unique valence electron structure of RE elements, especially the 4f electrons [3]. With increasing demands of modern applications, the development of novel RE materials becomes an unceasing topic. The application window of RE materials is mainly targeted by two aspects, the high-end utilization and balanced utilization of RE resources. In order to add value to RE resources, understanding the nature of RE materials formation and grasping the advanced techniques in RE materials engineering are indispensable.In the formation of RE materials, the chemical bonding between RE elements and ligands determines the local symmetry and crystal structure of the materials. Understanding the chemical bonding nature of RE elements becomes the most important task. The forces of electrostatic attraction between ions in a compound cause the chemical bonding of ions with the surrounding ions of opposite charge. However, it has been a longstanding mystery concerning 4f electrons of RE elements when evaluating their chemical bonding ability [4][5][6]. Very recently, we discovered that RE elements can form three types of chemical bonding, namely sp hybridization, spd hybridization, and spdf hybridization [7]. Furthermore, it is not necessary for all the valence electron orbitals to hybridize for these RE elements. Therefore, the coordination number of a *Corresponding author (email: dongfeng@ciac.ac.cn) central RE atom can have a wide range of values from 2 to 16, which means many infrastructures upon them can be designed by engineering their bonding environment. The relationship between the orbital hybridization set and coordination number of the RE element concerned enables us to easily clarify which orbitals participate in chemical bonding and how these orbitals distribute in the chemical bonding. It is worth noting that 4f electrons are only involved in chemical bonding when the coordination number of the RE element reaches 10 and above. It should be also mentioned that the origin of the 4f chemical bonding is weak interaction with long bond length.The foundation of RE materials science is 4f chemistry, which dictates the chemical reactions towards the development of novel RE materials. The recent advance in 4f chemical bonding [7] will stimulate the development of RE materials science. In 4f chemistry, the formation and breakage of chemical bonding involving 4f electrons occur in chemical reactions. Specially designed chemical reactions can therefore be used to control the formation of different types of chemical bonds (sp hybridization, spd hybridization, and spdf hybridization) in the synthesis of novel RE materials [8].Targeting the high-end utilization of RE resources, the development trend is to decrease the content of RE elements through substitution of oth...

show abstract

Transition Metal Oxide Work Functions: The Influence of Cation Oxidation State and Oxygen Vacancies

Greiner

Chai

Helander

et al. 2012

Adv Funct Materials

776

629

View full text Add to dashboard Cite

Transition metal oxides are capable of a wide range of work functions. This quality allows them to be used in many applications that involve charge transfer with adsorbed molecules, for example as heterogeneous catalysts, as charge-injection layers in organic electronics, and as electrodes in fuel cells. Chemical and structural factors can alter transition-metal oxide work functions, often making their work functions diffi cult to control. Little is known about the effects of the cation oxidation state and point defects on the oxide work function. It is necessary to understand how such chemical and structural factors affect work functions in order to controllably tune transition metal oxides for desired applications. Here, a correlation between the oxide work function and cation oxidation state is demonstrated. This correlation is attributed to the change in cation electronegativity with oxidation state. A model is presented that relates the work function to the oxygen defi ciency for d 0 oxides in the limit of dilute oxygen vacancies. It is proposed that the rapid initial decrease in work function, observed for d 0 oxides, is caused by an increase in the density of donor-like defect states. It is also shown that oxides tend to have decreased work functions near a metal/metal-oxide interface as a consequence of the relationship between defects and work function. These insights provide guidelines for tuning transition metal oxide work functions.

show abstract

Estimation of Electronegativity Values of Elements in Different Valence States

Cited by 672 publications

References 24 publications

Optical Basicity and Nepheline Crystallization in High Alumina Glasses

Optical Basicity and Nepheline Crystallization in High Alumina Glasses

4f chemistry towards rare earth materials science and engineering

Transition Metal Oxide Work Functions: The Influence of Cation Oxidation State and Oxygen Vacancies

Contact Info

Product

Resources

About