Here's what rhymes with tetraoctylammonium.
                        
                        
                    
                                ammonium  meconium  plutonium  zirconium  harmonium  polonium  pandemonium  Words that almost rhyme with tetraoctylammonium
chromium  amazonian  draconian  sodium  podium  linoleum  niobium  rhodium  europium  holmium  symposium  petroleum  opprobrium  colloquium  dysprosium