Organic compounds formulas list

The elements of an organic compound are listed in empirical formulas according to the Hill system [8] and the stoichiometry is indicated by index numbers. Hill positioned the carbon and the hydrogen atoms in the first and the second places, with heteroatoms following them in alphabetical order, e.g., C9H11NO2. However, it was recognized that different compounds could have the same empirical formula (see Section 2.8.2, on isomerism). Therefore, fine subdivisions of the empirical... 

If it is known, for example, that this is an organic compound, the list of possible elements is not too great, so, a comparison of this signal pattern with all other patterns of different molecular formulae, limited to those consistent with the information concerning the compound, allows its identification. 

The alkane series is also called the saturated hydrocarbon series because the molecules of this class have carbon atoms connected by single bonds only, and therefore have the maximum number of hydrogen atoms possible for the number of carbon atoms. These substances may be represented by the general formula C H2,I + 2 and molecules of successive members of the series differ from each other by only a CH2 unit. The line formulas and names of the first 10 members of the series, given in Table 21-2, should be memorized because these names form the basis for naming many other organic compounds. It should be noted that the first parts of the names of the later members listed are the... 

Many publishers make available their databases on floppy disks or CD-ROMs, which are often found inside the back cover of the book. An example is the Properties of Organic Compounds (Tide and Milne 1999), which is a CD-ROM list of 27,500 known organic compounds and their formulas, molecular weights, melting points, boiling points, densities, refractive indexes, colors, solubility scales, vapor pressures, and threshold limit values (TLVs) that workers can be exposed to in a normal 8 h workday and 40 h workweek. This reference gives only a limited number of properties, and does not go into flammability or toxicity. Solubility in water is given only as a... 

The simplest kind of formula is a compositional formula or empirical formula, which lists the constituent elements in the atomic proportions in which they are present in the compound. For such a formula to be useful in lists or indexes, an order of citation of symbols (hierarchy) must be agreed. Such hierarchies, often designated seniorities or priorities, are commonly used in nomenclature. For lists and indexes, the order is now generally recommended to be the alphabetical order of symbols, with one very important exception. Because carbon and hydrogen are always present in organic compounds, C is always cited first, H second and then the rest, in alphabetical order. In non-carbon-containing compounds, strict alphabetical order is adhered to. 

Beilstein is the most comprehensive list of organic compounds. The main series, volumes 1-27, 30 and 31, part I, covers the literature up to 1910. The first supplement, volumes 1-27, and the subject and formulae indexes constituting volumes 28 and 29, survey the literature up to 1919. The second supplement, volumes 1-27, and the subject and formulae indexes constituting volumes 28 and 29, covers the period 1920-1929. For compounds not listed in Beilstein , i.e., for those which first appear in the literature after 1929, the indexes of the Abstract Journals Chemical Abstracts, ChemischesZentralblatt or British Chemical Abstracts (to 1953) should be consulted. The Collective Formula Index to Chemical Abstracts, 1920-1946, is extremely useful. For general reference work Heilbron will be found less cumbersome than Beilstein , although of necessity not so comprehensive. 

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 most useful of these is Beilstein s Handbuch der organische Chemie, which lists the methods of preparation, the reactions, and the properties of all organic compounds which were reprorted in the years that are covered. The main series covers the literature up to 1909, the first supplement covers 1910—1919, and the second supplement covers 1920—1929. A third supplement, which has begun to appear, covers 1930—1949. There is a system which determines where a given compound win appear in the series, but with the advent of subject and formula indexes, there is no longer a need to become familiar with this system. 

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