text: Alkanediazonium salts are synthetically unimportant due to their extreme and uncontrolled reactivity toward S2/S1/E1 substitution. These cations are however of theoretical interest. Furthermore, methyldiazonium carboxylate is believed to be an intermediate in the methylation of carboxylic acids by diazomethane, a common transformation. 
  Loss of  is both enthalpically and entropically favorable:
  :, ΔH = −43 kcal/mol
  :, ΔH = −11 kcal/mol
  For secondary and tertiary alkanediazonium species, the enthalpic change is calculated to be close to zero or negative, with minimal activation barrier. Hence, secondary and (especially) tertiary alkanediazonium species are either unbound, nonexistent species or, at best, extremely fleeting intermediates. 
  The aqueous pK of methanediazonium () is estimated to be <10.