The Carbon Family

All three categories of elements occur within Group 4A(14), from the nonmetal carbon (C) through the metalloids silicon (Si) and germanium (Ge) and down to the metals tin (Sn) and lead (Pb) [Group 4A(14) Family Portrait, p. 434]. 

How Does the Bonding in on Element Affect Physical Properties  

Element Bond Type Melting Point (°C) AHfys (kJ/mol) 

Group electron configuration is ns np. Down the group, the number of oxidation states decreases, and the lower (+2) state becomes more common. Down the group, size increases. Because transition and inner transition elements intervene, IE and EN do not decrease smoothly. 

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Silicon (Si) is a nonmetallic chemical element of the carbon family (Group rva of the periodic table) and makes up 27.7 percent of the Earth s crust. It is the second most abundant element in the crust, being surpassed only by oxygen. 

It will pay you to know (without having to look in the periodic table or tables of electron configurations) that the halogens (F, Cl, Br, I, At) all have seven valence electrons, that the oxygen family (O, S, Se, Te) all have six, that the nitrogen family (N, P, As) have five, that the carbon family (C, Si) have four, and that the boron family (B) have three It will also pay you to know that electronegativities decrease from right to left in a row, or from top to bottom in a column, in the periodic table... 

Carbon is the definitive nonmetal, considering its vast variety of covalent compounds. The diamond structure (3 2PT, Section 4.4.3) has a network of tetrahedra. The next two elements of the carbon family, silicon and germanium, have the diamond structure, and lead is cubic close-packed. Tin shows an interesting variation. The low temperature form of tin (stable below 13.2°C) is gray tin with the diamond structure. The CN of Sn is 4, the Sn—Sn distance is 2.80 A and a0 = 6.4912. Ordinary tin, the "high temperature form, is white tin. In our time tin is used primarily for tin plate on iron for food containers, tin cans. In earlier periods utensils were often cast tin. In cold climates sometimes a tin utensil would crumble from "tin disease," resulting from conversion of white tin to gray tin. The conversion is slow, but once started, nucleation causes spread of the "disease."... 

FIGURE 2.2 Structural diversity in the carbon family and possibilities for accepting foreign species. 

Fullerenes behave as molecules [14], i.e., most of them can be dissolved into an organic solvent, giving a characteristic color, which is exceptional in the carbon families because all other materials are not dissolved in any organic solvent. 

Carbonates represent an important family of protecting groups of hydroxyl groups. All of the members of the carbonate family are easy to introduce by reaction of the free alcohol with chloroformates or mixed carbonate esters. In general, carbonates are less reactive than esters towards basic hydrolysis owing to the reduced electrophilicity of the carbonyl afforded by the resonance deactivation by two oxygens. However, the conditions that attack esters may also attack carbonates. 

Germanium is a metalloid. A metalloid is an element that has characteristics of both metals and non-metals. Germanium is located in the middle of the carbon family, which is Group 14 (IVA) in the periodic table. The periodic table is a chart that shows how chemical elements are related to each other. Carbon and silicon are above germanium and tin and lead are below it. 

Silicon and germanium have been found to form clathrate-type host lattices in which guest species are alkali atoms. The host lattices are exactly the same as those of type 1 and II hydrates "" (see 16.2.2). They are formed by atoms of only one kind, which are bonded together by strongly covalent forces, as in the Si or Ge diamond structures. The Si—Si or Ge—Ge bond lengths are of the same order of magnitude as in classical Si or Ge with the bond angles 109°28 which characterizes the tetrahedral sp hybridization of the carbon family. 

Consider the elements of Group 4A (the "carbon family") C, Si, Ge, Sn, and Pb. What is the trend in metallic character as one goes down this group What is the trend in metallic character going from left to right across a period in the periodic table ... 

The carbon family consists of carbon, silicon, germanium, tin, and lead. All these form oxides which look like CO (e.g., SiO, PbO ). They also form monoxides. As medical enthusiasts, you probably have heard of carbon monoxide, and its harmful effects. CO is a colorless and odorless gas, and it has even higher affinity for hemoglobin than oxygen in the red blood cells. 

Group 4A(14) The Carbon Family Highlights of Carbon Chemistry Highlights of Silicon Chemistry... 

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