The Transition Elements and Their Coordination Compounds

Exploring the Centerof the Table Many transition eiements, like the iron and chromium in this stainiess steei scuipture, are among the most useful metals known. In this chapter, you ll see why transition eiements and their compounds differ so markedly from main-group elements. 

According to valence bond theory, the shapes of complex ions arise from hybridization of different combinations of d, s, and p orbitals. 

Electron Configurations Atomic and Physical Properties Chemical Properties 

Structures of Complex Ions Formulas and Names Isomerism 

Valence Bond Theory Crystal Field Theory Complexes in Biological Systems 

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CHAPTER 22 The Transition Elements and Their Coordination Compounds... 

Organometallic chemistry does have its own distinctive flavour. Organometallic compounds are often (but not invariably) air- and moisture-sensitive and their handling requires much care and skill. In the interplay between kinetic and thermodynamic considerations, organometallic chemistry falls somewhere between inorganic and organic chemistry. Most organometallic compounds of the transition elements can also be classified as coordination compounds, and are dealt with in more detail in Chapter 8. (See also Section 10.5.)... 

Two ions are well-known for their highly anisotropic properties. Firstly, in the rare-earth family, Dy3+ which has a 6H15/2 ground state. The spin-orbit interaction is stronger than the crystal field effects. The ratio J /J can be of the order of 100 (Jj. = 0), gjj = 20 and gi = 0 this is practically an ideal case. Secondly, in the transition element series, the ion Co2+ is also characterized by anisotropic interactions (either in the tetrahedral or octahedral coordination), the anisotropy being however lower than in the case of Dy3+. J /J is about 0.5 for this ion. Some Fe2+ compounds also display a behavior approximating to the Ising model. 

The lanthanides, elements 58 through 71, constitute a so-called inner transition series, as do the actinides, elements 90 through 103. Scandium (21) and yttrium (39), together with the lanthanides, are traditionally referred to as the rare earth elements. The lanthanides, with 3+ ions and decreasing radii, show strong ionic bonding and weaker covalent bonding characteristics. As discussed below, the lanthanides tend to exhibit hard sphere or A-type behavior in their coordination compounds. 

G. Chemistry of the Transition Elements — Electronic structures, occurrences and recovery, physical and chemical properties of the elements and their compounds, coordination chemistry... 

The lanthanoids are sometimes simply called the rare earths, although strictly the earths are their oxides. Nor are they particularly rare they occur widely, usually together. All are silvery very reactive metais. The/electrons do not penetrate to the outer part of the atom and there is no /-orbitai participation in bonding (unlike the d-orbitis of the main transition elements) and the elements form tew coordination compounds. The main compounds contain ions. Cerium also has the highly oxidizing Ce ... 

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