Manganese heptoxide reacting with acetone. Manganese heptoxide (Mn2O7) is a very strong oxidiser which decomposes near room temperature. Acetone, (CH3)2CO, dripped onto manganese heptoxide, initiates the decomposition and produces an explosive reaction. The products are black manganese dioxide (MnO2) and oxygen (O2). Ozone (O3) is also produced, giving a strong smell to the substance. See K004 8349 for the initiation of the reaction.