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

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

• More than 250,000 words that aren't in our free dictionary
• Expanded definitions, etymologies, and usage notes
• Advanced search features
• Ad free!