How do I get the Topological Diameter of my structure in Chem3D

In Chem3D top menu bar go to Calculations and select "Compute Properties"
- Expand "Molecular Topology"
- Select Topological Diameter.


The Diameter (D) calculation: is the maximum such value for all atoms, and is held by the most outlying atom(s). Examples: Diameter: methane = 0; ethane = 1; propane = 2; n-butane = 3.

References

1.    Michel Petijean, "Applications of the Radius-Diameter Diagram to the Classification of Topological and Geometrical Shapes of Chemical Compounds", JCICS 32, 331-337 (1992).