[ekster]

Dear all,

I would like to know if there is any beautifully-sounding chemical term that distinguishes:
 - PAHs consisting of 3 benzene rings such as anthracene, and
 - PAHs consisting of 2 benzene rings, but with substitution between the rings, thereby creating a third ring (but not benzene-type) such as dibenzofuran and fluorene.

For clarity: Both types are three-ring PAHs. But do these types belong to different families of compounds? 

Kind regards, Joeri

[AWK]

Polycycllic aromatic hydrocarbons -name  hydrocarbons implies compound contains only carbon and hydrogen.
The other are hetero analogues of PAHs