English: Magnesium bis-cyclopentadienyl is a toxic and highly reactive compound used as source of magnesium acceptor in MOVPE semiconductor-manufacturing technology of GaAs, GaN and other group-V-III compounds. The stainless "bubbler" states "Federal law forbids transportation if refilled penalty up to $25.000 fine and 5 year imprisonment (49 U.S.C. 1809)".