Implicit Carbon and Hydrogen Atoms
For example, in the image below, the skeletal formula of hexane is shown. The carbon atom labeled C1 appears to have only one bond, so there must also be three hydrogens bonded to it, in order to make its total number of bonds four. The carbon atom labelled C3 has two bonds to other carbons and is therefore bonded to two hydrogen atoms as well. A ball-and-stick model of the actual molecular structure of hexane, as determined by X-ray crystallography, is shown for comparison, in which carbon atoms are depicted as black balls and hydrogen atoms as white ones.
Any hydrogen atoms bonded to non-carbon atoms are drawn explicitly. In ethanol, C2H5OH, for instance, the hydrogen atom bonded to oxygen is denoted by the symbol H, whereas the hydrogen atoms which are bonded to carbon atoms are not shown directly. Lines representing heteroatom-hydrogen bonds are usually omitted for clarity and compactness, so a functional group like the hydroxyl group is most often written −OH instead of −O−H. These bonds are sometimes drawn out in full in order to accentuate their presence when they participate in reaction mechanisms.
Shown below for comparison are a ball-and-stick model of the actual three-dimensional structure of the ethanol molecule in the gas phase (determined by microwave spectroscopy, left), the Lewis structure (centre) and the skeletal formula (right).
Read more about this topic: Skeletal Formula
Famous quotes containing the words atoms, hydrogen and/or implicit:
“The atoms of Democritus
And Newtons particles of light
Are sands upon the Red Sea shore,
Where Israels tents do shine so bright.”
—William Blake (17571827)
“The pace of science forces the pace of technique. Theoretical physics forces atomic energy on us; the successful production of the fission bomb forces upon us the manufacture of the hydrogen bomb. We do not choose our problems, we do not choose our products; we are pushed, we are forcedby what? By a system which has no purpose and goal transcending it, and which makes man its appendix.”
—Erich Fromm (19001980)
“The true colour of life is the colour of the body, the colour of the covered red, the implicit and not explicit red of the living heart and the pulses. It is the modest colour of the unpublished blood.”
—Alice Meynell (18471922)