Dinitrogen tetroxide, N2O4, an unstable dimer of nitric oxide;
nitric acid 73% with dinitrogen tetroxide 27% (=AK27) and kerosene/gasoline mixture (=TM-185) – various Russian (USSR) cold-war ballistic missiles (R-12, Scud-B,-D), Iran: Shahab-5, North Korea: Taepodong-2
The operation failed due to a leak of fuel and oxidizer from missile number six just prior to the start.