Carbon, Silicon, Germanium, and Tin

Complexes with Carbon, Silicon, Germanium, and Tin. [(n-Cp)M(CO)3] (M = Mo or W) react with (CN)2C CXC1 to form [(n-Cp)M(CO)3C(X) C(CN)2] derivatives (82) in which the metal is bonded to the unsaturated cyanocarbon system.  

CH2CH2CI)] (83) is treated with Na-Hg in THF the cyclic Mo—C compound so formed undergoes hydride elimination to give the cationic derivative of chelated allyldimethylarsine (84). The olefin can be displaced by cyanide. Although the corresponding cyclized derivative is formed for tungsten, no hydride elimination appears to occur.  

Molecules of tris(diphenylacetylene)tungstenmonocarbonyl (85) have a capped trigonal-prismatic (Cj, ) structure. The geometry of the acetylene groups is considerably altered by co-ordination, the C—C—CPh angles being ca. 140°.  

Malisch, H. Schmidbaur, and M. Kuhn. Angew. Chem. Internal. Edn., 1972, 11, 516. 

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TABLE 6.14. Structural and Energy Parameters Calculated at Various Theoretical Levels for XH4- "HE Complexes of Carbon, Silicon, Germanium, and Tin... 

After this preamble we may consider the Chlorine, Bromine and Iodine couphng constants in the tetrahahdes of Group IV Carbon, Silicon, Germanium and Tin. 

All of the binary tetrahalides of carbon, silicon, germanium, and tin have been made, and many mixed halides (of the type SiCl2F2) have also been characterized. Except for SnF4 (the most saltlike of the group), all of the tetrahalides are volatile. It is interesting (and not easily explained) that aside from CF4 and SiF4, the tetrahalides of silicon boil at lower temperatures than those of carbon. 

Reactions of B2F4 and B2CI4 with a number of monovinyl derivatives of boron, carbon, silicon, germanium, and tin have been investigated (28). Smooth addition was found in each case ... 

Intrinsic semiconductors. The group fourteen elements carbon, silicon, germanium, and tin can be found to adopt the diamond-type crystal structure shown in Figure 3 a. Other crystalline structures are also found for example, graphite and diamond are different crystal structures of the same element, carbon. Because of its size and orbital energies, carbon forms very... 

C. L. De Ligny and N. G. Van der Veen, Rec. Trav. Chim., 90, 984 (1971). Solubilities of some tetra-alkyl carbon, -silicon, -germanium, and -tin compounds in mixtures of water with methanol, ethanol, dioxane, acetone and acetic acid and differences between the standard chemical potentials of these solutes in their solutions in water and in the mixed or nonaqueous solvents at 25°C. 

Thus we have shown that when s and p orbitals are available and s—p quantization is broken an atom can form four (or fewer) equivalent bonds which are directed towards tetrahedron corners. To the approximation involved in these calculations the strength of a bond is independent of the nature of other bonds. This result gives us at once the justification for the tetrahedral carbon atom and other tetrahedral atoms, such as silicon, germanium, and tin in the diamond-type crystals of the elements and, in general, all atoms in tetrahedral structures. 

Fig. 4.—Radial distribution curves for carbon and silicon tetrafluorides and silicon, germanium and tin tetrachloride.

The mechanism shown in (25) can be described as an SN2 substitution at tin, or as an SE1 substitution at carbon catalysed by the ion OY, i.e. as mechanism Se1-OY-. A similar mechanism to that of (25) has also been postulated27 for the base-catalysed cleavage of 3-phenallyl derivatives of silicon, germanium, and tin these cleavages are more fully discussed in Chapter 10, Section 1 (p. 195). 

Tin is a member of Group 14 (IVA) in the periodic table. The periodic table is a chart that shows how chemical elements are related to one another. Tin is also part of the carbon family. Other carbon family elements include carbon, silicon, germanium, and lead. 

In the periodic table of the elements, tin is listed in group 14, together with the elements carbon, silicon, germanium, and lead. The four electrons... 

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