Special Nodes and R-groups

Special nodes

Name	Description
Homology groups	The drop-down list contains the default homology groups.
Pol	Pseudo atom Pol. This button changes the selected atom to a pseudo atom labeled Pol (polymer).
*	This button creates an ***** atom, which indicates an unspecified end group in polymers.

R-groups

These atoms can be used to describe unknown or unspecified molecule parts or to draw R-group queries or Markush structures.