Block metal chemistry general considerations

The three rows of fi -block metals are shown in the schematic periodic table at the beginning of the chapter. The term transition elements (metals) is also widely used. However, the group 12 metals (Zn, Cd and Hg) are not always classified as transition metals. The elements in the /-block (see Chapter 27) have, in the past, been called inner transition elements. Throughout our discussions, we shall use the terms fi -block and /-block metals, so being consistent with the use of the terms. s-block and p-block elements in earlier chapters. Three further points should be noted  

An important point that must not be forgotten is that c(-block metal atoms are, of course, many-electron species. 

In this section, we consider physical properties of the d-block metals (see cross-references in Section 19.1 for further details). An extended discussion of properties of the heavier metals is given in Section 22.1. Nearly aU the fi -block metals are hard, ductile and malleable, with high electrical and thermal conductivities. With the exceptions of Mn, Zn, Cd and Hg, at room temperature, the metals possess one of the typical metal structures (see Table 6.2). The metallic radii for 12-coordination (Table 6.2 and 

This last observation is due to the so-called lanthanoid contraction the steady decrease in size along the 14 lanthanoid metals between La and Hf (see Sectirai 27.3). 

Metals of the tf-block are (with the exception of the group 12 metals) much harder and less volatile than those of the s-block. The trends in enthalpies of atomization 

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Chapter 20 d-Block metal chemistry general considerations... 

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