Academic literature on the topic 'Polarizability. Electronegativity'

In this appendix, the parameters and properties of anion-forming elements and their ions are tabulated. Both atomic and anionic properties are outlined including element isotopes with non-zero nuclear spin, natural abundance, neutron coherent scattering length, ionization energy, electron affinity, and Pauling’s electronegativity, and anionic formal valence, electronic configuration, coordination number, ionic radius, and polarizability.

Since the accidental discovery of crown ethers, the field of supramolecular chemistry has grown by leaps and bounds. O, S- based macrocycles were developed early and their chemistry is so vastly available. In comparison to that, the higher chalcogen (Se/Te) containing macromolecules are very less in number. Over the years, Te based macrocycles have been reported and due to their greater s-character and lower electronegativity than the rest, their chemistry has been fascinating. Due to, Toxic nature of Te and higher polarizability of Te-C bond owing to huge difference in size as well as electronegativity between Te and C, the growth of chemistry of Te-containing macrocycles has got hindered. Te being a soft center, there has been numerous attempts where hard N center has been included in the same macromolecule, just to create a surrounding which is capable to bind a wide range of metal ions with different dimensions and oxidation states. There are reports of Schiff base as well as –NH– group containing Tellura-aza-macrocycles, including cryptands also. In this chapter the chemistry of different types of tellura-zaz-macrocycles have been discussed, where focus has been given on their synthesis and metal complexation with structural details.

Understanding the fundamental principles of chemical reactivity is crucial in the field of organic chemistry. This chapter explores three key concepts that govern the reactivity of organic compounds: acids, bases, and nucleophiles. The Brønsted-Lowry theory is introduced, which defines acids as proton donors and bases as proton acceptors. The strength of acids and bases, as measured by their pKa and pKb values, is discussed in detail, highlighting how it determines their ability to participate in proton-transfer reactions. Factors influencing acid and base strength, such as electronegativity, resonances, and inductive effects, were examined. The chapter also covers the role of nucleophiles in organic transformations, emphasizing how their reactivity depends on factors like charge, polarizability, and steric effects. Understanding the interplay between acids, bases, and nucleophiles provides a foundation for predicting and controlling the outcomes of a wide range of organic reactions, enabling the rational design of synthetic strategies and the development of new chemical processes.

Three sets of ionic liquids such as 1-alkyl-3-methylimidazole chloride [Cnmim]Cl, 1-alkyl-3-methylimidazolium acetate [Cnmim]Ac and 1-octyl-3-methylimidazole salt [Omim]Y (n = 2, 4, 6, 8, and Y = Cl, BF4, HSO4, Ac and TFO) were used as corrosion inhibitor medium for corrosion protection of carbon steel. Electronic structures and reactivity of these ionic liquids, surface energy and electronic structures of the iron surface were systematically analyzed by density functional theory. By increasing the alkyl chain length of the [Cnmim]Cl and [Cnmim]Ac systems, the lowest unoccupied molecular orbital energy (ELUMO), the highest occupied molecular orbital energy (EHOMO), the softness (S) and polarizability (α) increased gradually, whereas electronegativity (χ), energy gap (ΔE), hardness (η), dipole moment (μ)and electrophilic index (ω) gradually decreased. For the [Omim]Y system, the structure parameters of ionic liquids are quite different, and only the polarizability (α) decreases gradually by increasing the length of the alkyl chain. The results show that inhibition is mainly [Cnmim]+ cations of the [Cnmim]Cl system, and the order of inhibition efficiency follows as [C2mim]Cl < [C4mim]Cl < [C6mim]Cl < [C8mim]Cl. Both [Cnmim]+ cations and the Ac− anion have inhibition effect for the [Xmim]Ac system, and the order of inhibition efficiency is [C8mim]Ac > [C6mim]Ac > [C4mim]Ac > [C2mim]Ac. For the [Omim]Y system, [Xmim]+ cations and anions (BF4−, HSO4−, Ac−, TfO−) have inhibition effect, and the order of inhibition efficiency is [Omim]TfO > [Omim]Ac > [Omim]HSO4 > [Omim]BF4 > [Omim]Cl.