Condensed structures are easy to read and draw
Compare the condensed and expanded structural formulae shown below.
In condensed structures
Multiple-bonded carbons are bonded to fewer hydrogen atoms.
In condensed structures
- carbon-hydrogen bonds are not shown.Each carbon is followed directly by the hydrogen atoms bonded to it, the number of hydrogens being shown by the subscript.
- carbon-carbon single bonds are not shown for carbon chains written on the same line.Be careful to draw the bonds from chain to branch atoms from C to C. These are the carbon atoms bonded to each other.
- carbon-carbon multiple bonds are always shown using two or three lines, as appropriate.
Multiple-bonded carbons are bonded to fewer hydrogen atoms.
| 1 CH3CH2CH3 | 2 CH2=CHCH3 |
 |  |
| 3 HC≡CCH2CH3 | 4  |
 |  |
If the carbon atom at the end of the chain is
single-bonded it has 3 hydrogens (as in 1-4).
double-bonded it has 2 hydrogens (as in 2).
triple-bonded it has 1 hydrogen (as in 3).
double-bonded it has 2 hydrogens (as in 2).
triple-bonded it has 1 hydrogen (as in 3).