Lecture notes for chemical students. Vol. 2, Organic chemistry / by Edward Frankland.

  • Frankland, Edward, 1825-1899.
Date:
1872
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Licence: Public Domain Mark

Credit: Lecture notes for chemical students. Vol. 2, Organic chemistry / by Edward Frankland. Source: Wellcome Collection.

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    Others contain four elements—carbon, hydrogen, oxygen, and nitrogen. Some contain sulphur, chlorine, bromine, iodine, silicon, phosphorus, boron, or metals ; but these are comparatively rare. Although the number of the elements entering into the com¬ position of organic compounds is much smaller than that usually taking part in the formation of minerals, yet the complexity of the former class of compounds is frequently much greater. There is no instance of an organic molecule containing but two single atoms, and only one containing three (hydrocyanic acid, HCN). On the other hand, the number of atoms in a single organic molecule is sometimes very great. Thus :— The molecule of Spermaceti contains 98 atoms. JJ „ Stearin 33 173 „ „ Margarin 33 217 „ 3J „ Albumen 33 226 „ 33 „ Protagon 33 381 „ In nearly all organic compounds carhon is a tetrad. It forms, therefore, with 1 atom of hydrogen a triad compound radical, which exists in chloroform (CII)'Cl3; a dyad com¬ pound radical with 2 atoms of hydrogen, as in methyleuic dichloride (C ‘''II„)Cl2; and a monad compound radical with 3 atoms of hydrogen, as in methjdic iodide (C^Hj)!. But in these compounds it will bo seen that the cai’bon is always satu¬ rated and always a tetrad. This is in conformity with the following general law:—“ In every molecule of a chemical compound the sum of the bonds is always an even number,” because every number, whetber odd or even, when multiplied by 2 gives an even number. To this may be added the following law, to which no exception is known :—“ The sum of the bonds in any molecule is at least twice as great as the active atomicity of the most polyad cle¬ ment in the compound.” A compound organic radical is a p'oup of atoms containing one
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