The title compound, C6N6O3, displays crystallographic (6) over bar sym
metry. All atoms lie in mirror planes. The actual symmetry is close to
the ideal (6) over bar m2. Ring angles alternate between 112.37(9)deg
rees at the keto and 127.63(9)degrees at the diazo C atoms. The molecu
les form layers with hexagonal close packing.