Experimental and theoretical data for 5-azidotetrazole CHN7 and its phenyl derivative 5-azido-1-phenyltetrazole as well as tetrazolylpentazole are reported. We discuss their syntheses, their properties and the X-ray structures of 5-azidotetrazole and its phenyl derivative. The decomposition reactions of tetrazolylpentazole and 5-azidotetrazole were also investigated. We furthermore calculated the electrostatic potentials of 5-azidotetrazole, its methyl and phenyl derivatives and of tetrazolylpentazole to determine the relative sensitivity of these compounds.