Group 14 Metals - Tin and Lead

The ability of organotin compounds to self-assemble, with an increase of the coordination number of tin from four to five and six, has been recognized quite early, and the resulting compounds were termed autocomplexes [345]. 

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Group 14 Metals - Tin and Lead 171 3.3.1.6 Organotin derivatives of inorganic acids... 

Not all main-group elements readily form ions, however. Rather than gain or lose electrons, atoms of carbon and silicon form covalent bonds in which they share electrons with other atoms. Other elements tend to form ions that do not have noble-gas configurations. For instance, it is difficult for the Group 14 metals tin and lead to lose four electrons to achieve a noble-gas configuration. Instead, they tend to lose the two electrons in their outer p orbitals but retain the two electrons in their outer s orbitals to form 2-1- cations. (Tin and lead can also form molecular compounds in which all four valence electrons are involved in covalent bonding.)... 

Group 14 (IV A) (the carbon group) includes a nonmetal (carbon), silicon, and germanium, which are metalloids (Si behaves as a nonmetal mostly, but Ge behaves as a metal) and the typical metals, tin and lead. These elements have 4 electrons in the outer energy level, 2 of which are in the last p orbitals (p ) (Table 2.4). These 4 electrons are usually shared silicon and germanium can form +4 ions, tin and lead can form +2 ions, and only carbon can form -4 ions. 

Sihcon is a Group 14 (IV) element of the Periodic Table. This column iacludes C, Si, Ge, Sn, and Pb and displays a remarkable transition from iasulatiag to metallic behavior with increasing atomic weight. Carbon, ia the form of diamond, is a transparent iasulator, whereas tin and lead are metals ia fact, they are superconductors. SiUcon and germanium are semiconductors, ie, they look metaUic, so that a poHshed siUcon wafer is a reasonable gray-toned mirror, but they conduct poorly. Traditionally, semiconductors have been defined as materials whose resistance rises with decreasiag temperature, unlike metals whose resistance falls. 

Silicon (3), which resembles metals in its chemical behavior, generally has a valence of +4. In a few compounds it exhibits a +2 valence, and in silicides it exists as a negative ion and largely violates the normal valency rules. Silicon, carbon, germanium, tin, and lead comprise the Group 14 (IVA) elements. Silicon and carbon form the carbide, SiC (see Carbides). Silicon and germanium are isomorphous and thus mutually soluble in all proportions. Neither tin nor lead reacts with silicon. Molten silicon is immiscible in both molten tin and molten lead. 

Tin and lead are neighbors in Group 14 of the periodic table. Each metal displays two common oxidation states,... 

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