Topological index

A topological descriptor, often simply referred to as a topological index is a numerical value which is derived from the structure of a chemical molecule.

This number is used to correlate chemical properties and biological activity of the molecular structure.

The term topology is used because for the determination of the descriptor only one aspect of Molekülstuktur is always used, in particular, only the connectivity is usually considered, ie for example which atom is connected to which and how many bonds between two atoms lie.

Typically go

• Bond orders
• Distances between atoms
• Ring sizes
• Chain lengths

And sometimes atomic masses and types in the calculation.