diazo group

noun Chemistry.
  1. the bivalent group –N=N– united with one hydrocarbon group and another atom or group, as in benzenediazo hydroxide, C6H5N=NOH, or the bivalent group =N=N united with one hydrocarbon group, as in diazomethane, CH2=N=N.
Also called diazo radical.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018