Nitramene

Nitramene is a molecular compound first synthesized by Howard Stark of Earth-199999 that is highly volatile and explosive. Stark kept the formula for molecular nitramene in a vault along with several other of his more dangerous creations, which were all stolen from him in 1946 and soon spread across the black market—these suspicious circumstances led to congressional allegations that he was deliberately selling his creations to foreign elements. The nitramene surfaced in New York City, where it was quickly manufactured by an unknown criminal entity. Peggy Carter, as part of an effort to clear Stark's name, tracked down the nitramene, but has thus far been unable to isolate its distribution.