phenanthroline
noun
phe·nan·thro·line
fə̇ˈnan(t)thrəˌlēn,
-lə̇n
plural -s
: any of three crystalline nitrogen bases C12H8N2 related to phenanthrene and derivable from ortho-, meta-, and para-phenylenediamine; di-aza-phenanthrene
especially : the ortho or 1,10-isomer that forms a red coordination complex with ferrous ions useful as an oxidation-reduction indicator (as with potassium permanganate as oxidizing agent) because it becomes faint blue in the oxidized form
Word History
Etymology
International Scientific Vocabulary phenanthr- + quinoline