A major and continuing objective in the area of energetic materials is reduced sensitivity to accidental detonations due to unintended stimuli. These can include impact, shock, heat, friction, electric spark, etc. The challenge is to combine low sensitivity with a high level of detonation performance. Our research group has the capability to compute both detonation properties and and estimates of impact sensitivity for new or proposed energetic molecules. This can be very beneficial for the synthesis of these materials. Synthetic chemists may spend years developing synthesis for molecules that will end up to be too sensitive or which do not have good detonation properties. We have recently identified the free space available in the crystal as a factor that may play a role, along with a molecule's intrinsic properties, in a molecule's sensitivity. We are currently further investigating this factor.