A study has been made of the photolysis of mercurous azide and triphenyl methyl azide in the solid state. The decomposition has been followed as a function of light intensity, surface area, and temperature. The activation energy for photochemical decomposition is 0.37 eV for mercurous azide and 0.38 eV for triphenyl methyl azide. A number of the physical, optical and electrical properties of mercurous azide have been measured and the results obtained are consistent with a covalent-type solid. It is suggested that the first step in the decomposition of both these covalent azides is bond fission at the longest N-N bond in the azide group. The behaviour of the covalent azides is compared with that of the ionic azides described in part I.