Carbon The Element of Organic Compounds

Because carbon atoms can form strong bonds with one another while combining with other elements, the number of organic compounds is enormous. More than two million such compounds have been described and characterized,3 which is more than ten times the total number of known compounds of all other elements except hydrogen. 

For even more convenience in representing the structures of organic compounds, particularly in printed material, line formulas are used, so-called because they are printed on one line. In line formulas, each carbon atom is written on a line adjacent to the symbols for the other elements to which it is bonded. Line formulas show the general sequence in which the carbon atoms are attached, but in order to interpret them properly, the permitted total bond orders of all the respective atoms must be kept in mind. Again referring to the compounds (a) to (e) described above, the line formulas are as follows ... 

If you were asked to produce at ordinary temperatures a sample consisting of the free atoms of an element, your only choice would be a Group 18 element, one of the noble gases. All the other elements occur with their atoms linked together in some way. The nonmetallic elements exist as molecules, such as the diatomic species H2, N2, 02, F2, Cl2, Br2, and I2, and the polyatomic species P4 and S8. Elements near the border between metals and nonmetals can form solids with an extended network of atoms, such as the graphite or diamond forms of carbon and crystalline silicon. There are also countless examples of diatomic, polyatomic, and extended network compounds between different nonmetallic elements, including the millions of organic compounds. 

The number of organic compounds/ar exceeds that of inorganic compounds, but very few other elements are involved along with the ubiquitous carbon. 

Carbon and hydrogen have always been considered as two basic and mandatory elements of organic compounds. Recent discoveries in the area of caged structures, however, reveal that a whole family of closed shell compounds composed of pure carbon with the general empirical formula C should be included as well in the list of objects to be studied by organic chemistry. At present, only two individual compounds, 59 (Cso) and 60 (C70) (Scheme 4.18), have been prepared and unequivocally identified. 

The Composition of Organic Compounds has already been partially shown. They usually contain carbon and hydrogen, with or without oxygen, or nitrogen, or both a few contain sulphur, phosphorus, and other elements. When burned or heated they yield carbon, or carbon dioxide, water vapor, ammonia gas, sulphur compounds, etc., according to their composition. The general character of typical organic compounds may be shown by a study of the... 

It is not hydrogen that can bind together the elements of organic bodies. If, like carbon, it had the power to combine with itself, it would be possible to form the compounds H Cl, H Gl ,... 

Elemental analysis is the process for determining the partial or complete chemical formula for a substance. Most commonly, it involves the complete combustion in air or oxygen of the substance and then quantitating the amount of elemental oxides produced. In the case of organic compounds, the carbon is converted to carbon dioxide and the hydrogen to water. From these, the percent carbon and percent hydrogen in the substance can be found and compared with a proposed chemical formula for the substance at hand. 

In some instances the method for carbon determination has to be modified, e.g., the determination of trace amounts of what is referred to as dissolved organic carbon in water after inorganic carbon has been removed. This type of carbon determination involves wet oxidation activated by silver ions in a solution of potassium persulphate in sulphuric acid. The oxidation of organic compounds gives carbon dioxide, which is adsorbed by molecular sieves. The molecular sieves are then heated in a flow of helium to desorb the carbon dioxide, the amount of which is measured by a TCD. The lowest concentration of organic carbon that can be measured in water is 0.2—2ppm [55]. The application of chromatographic elemental analysis to the determination of the total carbon content in water has been described [56]. 

By the action of the cosmic radiation, nitrogen in the atmosphere is converted to radioactive carbon and tritium H. The radioactive carbon with a half-life of 5770 years and tritium with a half-life of 12.26 years enter the soil with precipitation, and together with radioactive potassium they are included into the biological circulation of elements. The principles of the formation and decay of radioactive carbon are used when determining the age of organic compounds in the organic debris and soils. 

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