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The contributions to this volume focus on selected chemical aspects of rare-earth materials. The topics covered range from a basic treatment of crystalline electric-field effects and chemical interactions in organic solvents, to separation processes, electrochemical beaviors which impact corrosion, oxidation resistance, chemical energy storage and sensor technology, and to analytical procedures. Underlying the most subtle chemical and optical properties of these elements and their compounds in the condensed state are the crystal field effects. This phenomenon in non-metallic compounds is discussed in chapter six. The volume opens with a review of important new solvent extraction procedures as well as emerging alternative separation processes such as photochemical separation, precipitation stripping and supercritical extraction. Scientific and industrial procedures are illustrated. In a further chapter eight major analytical techniques of obtaining accurate trace analysis are examined, tabulated and assessed. The most effective procedures of each are also reviewed. Chapter two considers a wide variety of methods using rare-earth solutions and slats to modify advantageously the costly deterioration of metals and alloys. This topic is expanded in the following chapter, paying particular attention to protection against high-temperature oxidation, sulfidization and hot-salt corrosion. The following two chapters are concerned with the versatility of the rare earths in addressing current technical problems such the use of rare-earth intermetallics, principally LaNi3-based materials, to provide the skyrocketing need for environmetally friendly, usually portable, battery power. The final chapter is a review of the solvation, interaction and coordination of rare-earth salts in a variety of organic solvents including dimethylacetamide, dimethylsulfoxide, various alcohols, acetonitrile and propylenecarbonate under strict anhydrous conditions. A contrast of these interactions with those in which water is present with organic solvents is also made.
Among the numerous applications of the rare-earth elements, the field of catalysis accounts for a large number. Catalysis represents approximately 20% of the total market sales of rare earths worldwide. As a matter of fact two main applications have been prominent in the last decades: zeolite stabilization for fluid cracking catalysts, and automotive post-combustion catalytic treatment.
Volume 15 in this series continues the voyage of discovery started almost a decade ago. Chapter 98 adds significantly to an evaluation of systematic, experimental low-temperature studies of the ambivalent behaviours of cerium (ferromagnetism, antiferromagnetism, spin glass, superconductivity etc.) which depend upon its environment in materials. The conclusions arrived at should provide new data against which the theory can be advanced. The next chapter provides a review of rare earth carbides, emphasizing the thermodynamics, phase diagrams, crystal structures and physical properties. The binary rare earth carbides present an exceptionally wide range of compositions and structures both as solids and gas-phase molecules. Complex carbides with additional metal and non-metal components also receive attention. Metal-rich halides (i.e. compounds with an X/R ratio <2) are the subject of the next chapter. The compounds are classified according to their structure and chemical bonding characteristics and their electrical and magnetic properties are also reviewed. Chapter 101 deals with the preparation, structure, chemical and physical properties of heavy-metal fluoride glasses. Large amounts of rare earths can be added into these, and they possess a great potential for optical applications in the mid-infrared range as fiber optic glasses for communication and transmission of information, optical wave guides, fiber lasers and sensors. The following chapter explores the chemical kinetics of solvent and ligand exchange in aqueous lanthanide solutions. A wealth of tabulated information on rate and equilibrium constants is provided in textual and tabular form. Chapter 103 considers the fundamentally important reactions of the lanthanide ions with water. These interactions are discussed for both solids and solutions. The hydrated species are considered in detail for the aqueous solution, revealing the consequences of the lanthanide series sequence. The concluding chapter reviews macrocyclic complexes formed by rare earth and dioxouranium ions as templates. Synthetic trends and reactivity are considered as well as potential uses of these intriguing wrap-around structures.
The rare earths play a unique role in science. These seventeen related elements afford a panoply of subtle variations deriving from the systematic development of their electronic configurations, allowing a test of theory with excellent resolution. In contrast they find widespread use in even the most mundane processes such as steel making, for polishing materials and gasoline cracking catalysts. In between are exotic uses such as TV screen phosphors, lasers, high strength permanent magnets and chemical probes. This multi-volume handbook covers the entire rare earth field in an integrated manner. Each chapter is a comprehensive up-to-date, critical review of a particular segment of the field. The work offers the researcher and graduate student alike, a complete and thorough coverage of this fascinating field.
This volume differs somewhat from the previous volumes in the
series in that there is a strong emphasis on the physical aspects
and not so much on the chemical aspects of intermetallic compounds.
Two of the chapters are concerned with relatively new experimental
methods of studying rare earth metallic phases - high energy
neutron spectroscopy and light scattering. In these chapters the
authors explain the new kinds of information one obtains from these
techniques and how this complements the knowledge previously
gleaned from the more common measurements - such as NMR, heat
capacities, magnetic susceptibility, transport and elastic
properties. One of the remaining three chapters deals with NMR
studies of rare earth intermetallics and the final two chapters are
concerned, not so much with a particular experimental technique,
but with physical phenomena that occur in these compounds: the
electron-phonon interaction and heavy fermion behavior.
This volume of the Handbook is the first of a two-volume set of reviews devoted to the rare-earth-based high-temperature oxide superconductors (commonly known as hiTC superconductors). The history of hiTC superconductors is a few months short of being 14 years old when Bednorz and Muller published their results which showed that (La, BA)2CuO4 had a superconducting transition of ~30 K, which was about 7K higher than any other known superconducting material. Within a year the upper temperature limit was raised to nearly 100K with the discovery of an ~90K superconducting transition in YBa2Cu3O7-&dgr;. The announcement of a superconductor with a transition temperature higher than the boiling point of liquid nitrogen set-off a frenzy of research on trying to find other oxide hiTC superconductors. Within a few months the maximum superconducting transition reached 110 K (Bi2Sr2Ca2Cu3010, and then 122K (TlBa2Ca3Cu4O11. It took several years to push TC up another 11 K to 133 K with the discovery of superconductivity in HgBa2Ca2Cu3O8, which is still the record holder today.
This volume of the handbook covers a variety of topics with three
chapters dealing with a range of lanthanide magnetic materials, and
three individual chapters concerning equiatomic ternary ytterbium
intermetallic compounds, rare-earth polysulfides, and lanthanide
organic complexes. Two the chapters also include information of the
actinides and the comparative lanthanide/actinide behaviors.
Even at the beginning of the new millenium the rare earths still
remain, to a certain extent, a mystery. The chapters in this volume
will help to unravel some of these. In the filling of the 4f
electronic orbitals the lanthanides defy the elementary aufbau
principle that underlies the periodic sequence of the elements, and
the authors of the first chapter introduce the readers to the basic
physics of the orbital collapse leading to that failure.
Furthermore an explanation is offered in terms of double-well
potentials. The phenomenon is illustrated using the valence
transitions observed in some of the rare earth atoms, including Sm
group metals and the higher oxides of cerium, praseodymium and
terbium. In the second chapter the synthesis and structure of the
many types of rare earth halides are described. They have been
described as simple, complex, binary, ternary and multinuclear
complex, and other categories needed to deal with the most studied
of the rare earth compounds. The structure types are skillfully
illustrated to show the elementary architecture of each type.
The simple words of love from a gentle heart. Selected works of poetry
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