Azide XN3 are highly energetic compounds relevant for click chemistry.  We have investigated the ultrafast photodissociation of ClN3 in two energy range, one leading to an azide radical in its linear form and another one leading to its cyclic form. Both the energy balance and the momentum one are recorded at the femtosecond scale. This first experimental investigation of azide compounds in the femtosecond domain shows that the emission angle of the fragments relative to the pump polarisation changes during the dissociation time drastically for the cyclic radical compared to the linear one.