Closely related to octanitrocubane, heptanitrocubane is a new experimental high explosive based on the cubic eight-carbon cubane molecule. Seven of the eight hydrogen atoms at the corners of the cubane molecule are replaced by nitro groups, giving the final molecular formula C8HTemplate:Nitro.
As with octanitrocubane, not enough heptanitrocubane has been synthesized to perform detailed tests on its stability and energy. It is hypothesized to have slightly better performance than explosives such as HMX, the current high-energy standard explosive, based on chemical energy analysis. It is not as energetic as octanitrocubane, though.