Glossary

graph

A collection of nodes connected by edges.

chemical graph

A graph where atoms are nodes and bonds are edges.

molecular graph

A connected chemical graph representing a single molecule.

complete chemical graph
complete molecular graph

A chemical graph or molecular graph with all atoms and bonds present where all atoms have known elements and formal charges and all bonds have known bond orders. Contrast connectivity graph.

connectivity graph

A chemical graph that includes all bonds and atoms, but not necessarily their formal charges or bond orders; ie, it defines the connectivity of a chemical system. Contrast molecular graph, chemical graph.

connected

A connected graph is one in which for any two nodes \(a\) and \(b\) there exists some collection of edges that form a path from \(a\) to \(b\). That is, you can’t split the graph into subgraphs that have no edges between them.

linking atom

An atom in a residue or residue definition that forms a bond with an atom in another residue.

leaving atom

An atom in a residue or residue definition that is removed when a bond between linking atoms is formed.