repeat unit - a specific arrangement of atoms that recurs over and over again in a
macromolecule. The repeat units are usually arranged in long
chains. Since macromolecules contain thousands of atoms, it would be impossible to draw the
complete molecular strucutre of a macromolecule on paper
or on a computer screen. So scientists just draw the repeat unit, inside brackets, like this:
the repeat unit of nylon 6-6
When you see a repeat unit drawn in brackets like this, you then know that many of the repeat
units are joined together in a long chain. The subscript n stands for a very large
number. In nylon 6-6, n is usually between 50 and 100, while in other macromolecules
n may be in the hundreds of thousands.
