8 HN3-1/3 + Br20 2 N-IIIH4Br-I + 11 N20

This is an oxidation-reduction (redox) reaction:

2 Br0 + 2 e- 2 Br-I (reduction)

22 N-1/3 - 22/3 e- 22 N0 (oxidation)

2 N-1/3 + 16/3 e- 2 N-III (reduction)

Br2 is an oxidizing agent, HN3 is a reducing agent, HN3 is an oxidizing agent.