The atmospheric chemistry of organic nitrates

Publisher Summary This chapter discusses molecular refractivity and polarizability. Refractive indices ( n ) of pure substances are more accurately measurable than any other optical properties. The refractive index of a substance varies with its physical state, temperature t , and wave-length λ of the light by which n is observed. The first two of these effects are attributed to the density d . The specific refraction r of a substance multiplied by the molecular weight is referred as molecular refraction. Polarizability of a particle is defined as the dipole moment induced by an electric field of unit intensity. The polarizabilities of monatomic ions and molecules are generally independent of field direction. The principal polarizabilities of molecules can be analyzed in terms of anisotropic bond polarizabilities. Polarizabilities are also responsible for the birefringence, which appears whenever the orientations of anisotropic molecules in an assemblage are derandomized or changed by any disturbing force.

Molecular Refractivity and Polarizability

The second part of this compendium concludes with a collection of phase change enthalpies of organic molecules inclusive of C11–C192 reported over the period 1880–2015. Also included are phase change enthalpies including fusion, vaporization, and sublimation enthalpies for organometallic, ionic liquids, and a few inorganic compounds. Paper I of this compendium, published separately, includes organic compounds from C1 to C10 and describes a group additivity method for evaluating solid, liquid, and gas phase heat capacities as well as temperature adjustments of phase changes. Paper II of this compendium also includes an updated version of a group additivity method for evaluating total phase change entropies which together with the fusion temperature can be useful in estimating total phase change enthalpies. Other uses include application in identifying potential substances that either form liquid or plastic crystals or exhibit additional phase changes such as undetected solid–solid transitions or behave ani...

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Phase Transition Enthalpy Measurements of Organic and Organometallic Compounds and Ionic Liquids. Sublimation, Vaporization, and Fusion Enthalpies from 1880 to 2015. Part 2. C11–C192

Microwave spectrum of nitramide

Publisher Summary The pyrylium salts represent one of the fundamental heterocyclic systems and are the basis of important natural products such as the anthoeyanins. This chapter reviews the scope, nomenclature, formulation, and syntheses of pyrylium salts. The syntheses of pyrylium salts are classified into three groups, according to the number of building blocks required to form the ring in a one-step process. The three groups are: (1) one-component syntheses, (2) two-component syntheses, and (3) three-component syntheses. Pyrylium salts bearing aromatic or heterocyclic substituents, or possessing fused saturated rings and considered as monocyclic pyrylium salts are discussed. A number of reactions starting from pyrylium salts and involving substitution at the pyrylium ring, or modification of existing substituents are also described. Pyrylium salts are useful intermediates in the conversion of aliphatic starting materials into aromatic carbocyclic or heterocyclic compounds. Some practical applications of pyrylium salts emerged are: fluorescent dyes, photosensitizers for silver halides, or photographic emulsions.

Pyrylium Salts Part I. Syntheses

11. Studies in dielectric polarisation. Part XV. The dipole moments of five-membered nitrogen ring compounds: indole, skatole, carbazole, isatin, phthalimide, and succinimide

James R. Partington

Papers

11. Studies in dielectric polarisation. Part XV. The dipole moments of five-membered nitrogen ring compounds: indole, skatole, carbazole, isatin, phthalimide, and succinimide

293. Studies in dielectric polarisation. Parts VIII, IX, X, and XI

29. Studies in dielectric polarisation. Part V. Benzene solutions of pyrones, thiopyrones, and thioketones. Dioxan solutions of ureas and thioureas

87. Studies in dielectric polarisation. Parts VI and VII

427. Studies in dielectric polarisation. Part II, III, and IV