Amplified Plasma Grenades are advanced weapon’s meant to be used with the integrated small launcher attached to carbines and heavy rifles, but strong enough soldiers should be able to throw it far enough to be safe.
Since Elerium is still in relatively short supply, and the plasem grenade reaction chamber was considered unworthy of re-engineering. The warhead was instead doped with metallic hydrogen.
Metallic hydrogen is a form of degenerate matter with a metal-like lattice organization. We can produce it in either solid or liquid form, depending on our needs. With our ability to manipulate matter using electromagnetic and gravitic fields, coupled with improvements in power generation, production has become more and more cost effective over the last two years.
Metallic hydrogen has roughly thirty five times the explosive capacity of TNT… among other uses. X-com has been able to conventionally increase the yield of things like plasma grenade, or non-plasma warheads, by using this technology. Most importantly, it allows them to save on Elerium 115, which still can't be synthesized.