c15h10

from The Collaborative International Dictionary of English v.0.48

Fluoranthene \Flu`or*an"thene\, n. [Fluorene + anthracene.]
   (Chem.)
   A white crystalline hydrocarbon {C15H10}, of a complex
   structure, found as one ingredient of the higher boiling
   portion of coal tar.
   [1913 Webster]