C19H40

from The Collaborative International Dictionary of English v.0.48

Nondecane \Non*dec"ane\, n. [L. nonus ninth + decem ten.]
   (Chem.)
   A hydrocarbon of the paraffin series, a white waxy substance,
   {C19H40}; -- so called from the number of carbon atoms in the
   molecule.
   [1913 Webster]