Families carbon

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. 

Symbol Sn atomic number 50 atomic weight 118.69 a Group IV A (Group 14) metaUic element of carbon family electron configuration Kr] 4di°5s25p2 valence states +2, +4 atomic radius 1.41 A electronegativity 1.7 standard electrode potential, E° for Sn2+ -i- 2e Sn is -0.1375 V ten naturally-occurring sta-... 

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... 

Triatomic fragments involving boron and carbon, such as those found in many borocarbide structures,16 show typical valence electron counts ranging between 12 and 16 electrons. These counts are unusual for isolated triatomic molecules, which usually have 16 or more electrons, unless one of the terminal atoms is FI (12 electrons).17 Within the boron-carbon family, four of six possible arrangements for the trimeric fragments have been observed (1) C—C-C, (2) C-B-C, (3) B-B—C, and (4) B-C-B. Coincident-ally, only those with D,h point symmetry occur in metal borocarbides. They include (1) CCC units in Sc3C4 18 (2) CBC units in Si BCj 19,20... 

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."... 

In this chapter, an overview on structures and textures of carbon materials is presented, through introducing a concept of carbon families, before going into the chapters concerning the detailed... 

FIGURE 2.1 Construction of organic hydrocarbons and inorganic carbon families, using the sp, sp2, and sp hybrid orbitals. 

Based on the extension by the repetition of three kinds of C-C bonds to infinite molecules, we may define carbon families, consisting of diamond, graphite, fullerenes, and carbynes [1], In each family, the structure shows characteristic diversities representative structures are listed in Figure 2.2. The detailed diversity in structure will be explained in the following sections for each family. Most structures in each family are thermodynamically metastable, and the family is represented by the allotrope name. In Figure 2.2, some possibilities to accept foreign species are also illustrated. 

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. 

Inagaki, M. and Kang, F. Carbon families. In Carbon Materials Science and Engineering, Beijing, China Tsinghua University Press, 2006 23. 

BPF Polycarbonate. The synthesis of bisphenol fluorenone polycarbonate was first reported by Morgan (2). As in that study, the BPF carbonate family reported here was made by an aqueous caustic/organic liquid interfacial polymerization. In our case the monosodium salt of... 

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. 

Solids based on sp hybridization, although subject of intense experimental efforts, seem to be the most elusive of the different carbon families [5]. The existence of linear chains of carbon atoms linked by alternating single and triple bonds (polyyne) or double bonds (polycumulene) with stabilizing molecular complexes at the end of the chains, has been recognized in interstellar molecular clouds and can be artificially produced by different chemical routes [6-8],... 

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