Organic Structures - Organic Chemistry Concepts: An EFL Approach - page 2

The tetravalent nature of the bonding of carbon. This means that carbon
needs four bonds to complete an octet of electrons, in other words to fill
its valence outer shell.

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The ability to form strong single covalent bonds where the bonded atoms
share an electron pair. Carbon atoms can bond in this way to an almost
unlimited number of other carbon atoms. For acyclic compounds there
are no rings. This gives either straight chains which have no branch
points, or branched chains which do have branch points. In cyclic com-
pounds there can be different sized rings.

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The ability to form double or triple multiple bonds , where more than
one electron pair is shared with another carbon atom.

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The ability to bond covalently with many heteroatoms , other non-carbon
atomic species such as H , O , N , S , P , and halogens. These bonds are either
single or multiple.

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1.3 MOLECULES, FORMULAE, AND STRUCTURES
Carbon can be part of different bonding arrangements in the group of bonded
atoms that form a molecule . Because a molecular formula only gives the type
and number of atoms in a molecule, it does not tell anything about the structure
of the molecule. The structure gives information of how the atoms are joined
together. For example, 366,319 structures with a molecular formula of C 20 H 42
are possible. To simplify this problem, it is necessary to classify and subclassify
organic substances.

The best place to start is with hydrocarbons , which are compounds that con-
tain only carbon and hydrogen. Figure 1.1 shows how related structures and
properties are used to classify hydrocarbons. As a first stage, hydrocarbons can