Biography:

One of their most recent publications is Anomalously large effects of pressure on electron transfer kinetics in solution: The aqueous manganate(VI)-permanganate(VII) system. Which was published in journal Physica B+C.

More information about T.W. Swaddle research including statistics on their citations can be found on their Copernicus Academic profile page.

T.W. Swaddle's Articles: (13)

Anomalously large effects of pressure on electron transfer kinetics in solution: The aqueous manganate(VI)-permanganate(VII) system

AbstractThe classical Stranks-Hush-Marcus theory of pressure effects on the rates of outer-sphere electron transfer reaction rates in solution underestimates |ΔV∗| specifically, for the MnO4/MnO42− (aq) exchange, ΔV∗=−21.2 (observed) vs. −6.6 cm3mol−1 (calculated). This discrepancy can best be resolved by conceding that the Mn-Mn separation σ in the transition state is variable and pressure-sensitive in the context of non-adiabatic electron transfer within an ellipsoidal cavity with σ ∼ 550 pm.

The vibrational spectra of simple cobalt(III) and chromium(III) ammine complexes

AbstractLaser Raman spectral data are presented for solid [Co(NH3)6]X3 (where X = Cl, Br and I), [Co(NH3)5Cl]Cl2, cis- and trans-[Co(NH3)4Cl2]Cl, and the sulfate and pentachlororocuprate (II) of Cr(NH3)63+, together with Raman spectra of aqueous solutions of Co(NH3)63+ and Co(NH3)5Cl2+ salts. Difficulties in obtaining Raman spectra of some Cr(NH3)63+salts are exlained in terms of photochemical reactions. The assignments of the metal-ligand vibrational spectra of these complexes are discussed; previous controversy has arisen through the occurrence of Raman-active bands in the infrared spectrum. The A1g cobalt-ammine stretching vibration appears twice in the Raman spectra of solid hexaamminecobalt(III) chloride and bromide, because of low crystal lattice symmetry.

Preface

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Chapter 1 - Importance of Inorganic Chemistry

Publisher SummaryInorganic chemistry represents the traditional core of chemistry, with a history traceable over thousands of years. The systematization of inorganic chemistry depends largely on the periodic table. In Mendeleyev periodic table, the elements of like properties are arranged in vertical columns and show atomic weights increasing left to right across a given row. Mendeleyev recognized several gaps in the table, corresponding to then unknown analogs of aluminum and silicon, and the properties of the missing elements, such as gallium and germanium were predicted. The periodicity of chemical properties arises from filling of successive quantum mechanical shells of electrons. Inorganic chemistry draws its strength from its great practical utility. The most rapidly developing technologies, such as communications, electronics, energy generation and conservation, environmental protection, and aerospace, have generated demands for new materials with unprecedented physical properties or compositional control. Many of the current research activities in inorganic chemistry are directed toward meeting these needs.

Chapter 4 - Crystalline Solids

Publisher SummaryWith the advent of powerful digital computers, determination of structure has become routine in modern research in synthetic chemistry.When the powdered crystalline solid diffracts monochromatic X-radiation,the diffraction pattern will be a series of concentric rings, rather than spots, because of the random orientation of the crystals in the sample. The structural information in this pattern is limited; however, because even solid compounds that have the same structure but different composition will almost inevitably have different d values, each individual solid chemical compound will have its own characteristic powder diffraction pattern. Both the positions and the relative intensities of the features are important in interpretation of powder diffraction patterns, although it should be borne in mind that diffraction peak heights in the readout from the photon counter are somewhat dependent on particle size. Bonding in solids takes several forms. Some elements, such as carbon or compounds, such as silica (SiO2) can form quasi-infinite networks of covalent bonds. These crystalline solids are typically very high melting; on the other hand, small, discrete molecules like dihydrogen (H2) or sulfur (S8) interact only weakly with one another through van der Waals forces and form low melting crystals. The concept of close packing is particularly useful in describing the crystal structures of metals, most of which fall into one of three classes: hexagonal close packed, cubic close packed (fcc), and body-centered cubic (bcc).

Chapter 5 - The Defect Solid State

Publisher SummaryOne of the defects in solid state includes point defects, which are limited to a single point in the lattice, although the lattice buckles locally so that the influence of point defects may spread quite far. This defect includes Schottky or Frenkel defects; the existence of both of these defects, within an ionic solid provides a mechanism for significant electrical conductance through ion migration from site to empty site. The other defects described are line defects that extend in 1D and may originate in an incomplete layer of atoms or from mismatching of layers. Line defects create lines of weakness in the crystals that may initiate fracture under stress. Plane defects are, in effect, grain boundaries. Large crystalline specimens are usually made up of microcrystals, or grains, the lattices of which do not match precisely with those of their neighbors. Impurities tend to be concentrated in the regions of mismatch. Large crystals may also contain sizable inclusions of the solution from which they were grown. Crystal surfaces may be viewed as vast defects in as much as the lattice forces are incompletely balanced. The effects of this imbalance are partially offset by distortion of the crystal lattice near the surface, but crystal surfaces still show a strong tendency to adsorb other molecules.

Chapter 9 - Nitrogen, Phosphorus, and Potash in Agriculture

Publisher SummaryAgriculture depends on a sufficient supply of inorganic nutrients to plants, such as carbon dioxide, water, nitrogen, sulfates, and phosphates. Atmospheric nitrogen is fixed in nature by certain soil bacteria, blue-green algae, and microorganisms in the root nodules of legumes. This is accomplished either by oxidation to nitrate or reduction to ammonia or ammonium salts. Atmospheric N2 and O2 combine endothermically in small but significant yield and at a sufficiently rapid rate above about 2000 K, but the gases must be quenched rapidly if the high-temperature yield of NO is to be recovered for subsequent conversion to nitric acid. The direct gas-phase synthesis of ammonia from nitrogen and hydrogen is presently the cornerstone of the fertilizer industry. Sulfur is an important plant nutrient, and some soils are sulfur deficient and accordingly require additions of sulfate or elemental sulfur. However, sulfur is less frequently the limiting factor in plant growth than is fixed N or soluble phosphates. The chief role of SO42- in (NH4)2SO4 fertilizer is a benign vehicle for the ammonium ion. Phosphorus is essential for plant growth and is often the limiting nutrient in aquatic ecosystems.

Chapter 10 - Sulfur and Sulfur Compounds

Publisher SummaryElemental sulfur occurs naturally in association with volcanic vents and as underground deposits. These are later mined by injecting air and superheated water, which melts the sulfur and carries it to the surface in the return flow. Most of the sulfur used in industry, comes as a byproduct of the desulfurization of fossil fuels. The Claus process is applicable in any industrial operation that produces hydrogen sulfide (H2S); it converts this highly toxic gas to nontoxic, relatively unreactive, and easily transportable solid sulfur. H2S has a familiar rotten-eggs smell, and there is a tendency to underestimate it as a mere malodorous nuisance with comic associations. It is extremely toxic—about three times as toxic, weight for weight, as hydrogen cyanide and can kill gas field workers who walk unwittingly into high concentrations of the gas. Elemental sulfur exhibits complicated allotropy, that is, it exists in many modifications. Most sulfur (90%) is converted to sulfuric acid. It is currently produced by burning elemental sulfur from the Claus or Frasch processes in air to obtain sulfur dioxide, catalytically oxidizing the SO2 with air to sulfur trioxide, and then hydrolyzing the SO3 to H2SO4. Alternative sources of SO2 include roasting of sulfide ores and burning of high-sulfur fossil fuels. Sulfur dioxide, which is mostly made by burning sulfur is usually marketed as the liquid and has many uses.

Chapter 11 - Alkalis and Related Products

Publisher SummaryThis chapter provides an overview of industrial alkalis that include the weak alkali ammonia, caustic soda, and lime. Lime is obtained by burning limestone and is one of the most important of all chemical commodities. It is the most economical source of alkali for many industries and agriculture. It is used in steelmaking and other metallurgical operations, in control of air pollution from smokestack gases, in water and sewage treatment, in pulp and paper production, in reduction of soil acidity, in cement and concrete manufacture, and in many chemical processes, such as papermaking. Sodium carbonate is a widely used source of mild alkali, either in hydrated form of big, glassy crystals—washing soda or as the powdery anhydrous solid—soda ash.

Chapter 15 - Oxidation and Reduction in Solution

Publisher SummaryThis chapter deals with the oxidation and reduction that take place in electrochemical cells, such as galvanic cells. In these cells, an external electric current is produced by an internal chemical reaction. A complete galvanic cell is a combination of two half cells. These half cells contain electrodes—oxidation occurs at the anode and reduction occurs at the cathode. The electromotive force (EMF, in volts) of the cell will depend on the identity of the half cells, the temperature and pressure, the activities of the reacting species, and the current drawn. An EMF will also be generated by a cell in which the two half cells are the chemically identical except for a difference in reactant activities. The chemical reactions in these two half cells provide the energy for the galvanic cell operations. A set of standard half-cell EMFs or the standard electrode potential, E° is the measure of potential of a reversible electrode at standard state. The chapter includes several examples to describe the manipulation and use of electrode potentials.

Chapter 16 - Corrosion of Metals

Publisher SummaryThis chapter focuses on corrosion of metals in aqueous systems, as this is a major engineering and economic problem. Aqueous corrosion of metals is much more important than dry oxidation of metals at near-ambient temperatures, because, if liquid water is present, diffusion of the ions and molecules involved in the electrochemical corrosion process is greatly facilitated. Most corrosion problems encountered in practice involve only a single metal. In bimetallic corrosion, the anodic and cathodic surfaces are well defined as being different metals, and are established instantly on placing the metals in electrical contact. The corrosion that results can be very vigorous, but one can usually arrange either to avoid using dissimilar metals together or else to place an electrically insulating gasket between them. Even single metals, however, are subject to aqueous corrosion by essentially the same electrochemical process as for bimetallic corrosion. The metal surface is virtually never completely uniform; even if there is no preexisting oxide film, there will be lattice defects, local concentrations of impurities, and, often, stress-induced imperfections or cracks, any of which could create a local region of abnormally high free energy that could serve as an anodic spot. This electrochemical differentiation of the surface means that local galvanic corrosion cells will develop when the metal is immersed in water, especially aerated water. A more effective source of anodic and cathodic regions on a single metal is variation in the thickness, or even local absence of a protective oxide film.

Chapter 17 - Extractive Metallurgy

Publisher SummaryThis chapter discusses several methods for the extraction of metals from minerals. The simplest concentration technique is the use of gravity to separate dense metal or ore particles from the much less dense silicate and other rock-forming minerals by suspending the latter, finely divided in swirling water. Froth flotation is another method that is widely used to concentrate ores, particularly sulfides such as galena (PbS), although it is by no means restricted in use to metallic sulfides. In the case of metal sulfides, the crushed rock is suspended in water, and the particles of metal sulfide, which may be denser than the unwanted siliceous gangue, are nevertheless caught up in a froth generated by blowing air through the mixture after addition of a frothing agent, such as pine oil. The froth can then be skimmed off the top and the metal sulfide recovered. Hydrometallurgical methods use reactions in aqueous solution to concentrate and/or separate the metal ions of interest, such as the heap leaching of low-grade copper ores with acid. Difficult separations can often be effected by liquid–liquid solvent extraction, which depends on differences in the distribution of solute species between two immiscible or partially immiscible phases.

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