Via Instapundit, we have this:

When most bombs go off, they release a spray of deadly shards of steel. Now, imagine that those shards were themselves explosive, detonating in a massive chain reaction. It’s for real: Defense contractors are harnessing the strange alchemy of reactive materials (RMs) — in which two or more inert materials are mixed to create an explosion — to develop smaller, more lethal warheads, as well as new ways to protect troops against mortar rounds and rocket-propelled grenades.