azoindoxyl

azo +‎ indoxyl

azoindoxyl (plural azoindoxyls)

1. (organic chemistry) Any indoxyl that contains a two atom nitrogen group (-N=N-) uniting two hydrocarbon radicals, typically used for dyes in electron microscopy.
   • 1970, M. A. Hayat, Principles and Techniques of Electron Microscopy, page 252:

     For example, certain sulfur-containing dyes reduce osmium tetroxide to osmium black, which is electron opaque (Hanker et al., 1964), and certain azoindoxyls form insoluble osmium-containing complexes ( Holt and Hicks, 1966).

   • 2006, José Luis Millan, Mammalian Alkaline Phosphatases, page 254:

     The nitro-blue tetrazolium method with menadiol diphosphate was found to be superior to existing methods employing azo, azoindoxyl or tetrazolium salts and to metal precipitation methods.