Quoting from the Abstract:<p>> Wigner and Huntington first predicted that pressures of order 25 GPa were
required for the transition of solid molecular hydrogen to the atomic metallic phase. Later it was predicted that metallic hydrogen might be a metastable material so that it remains metallic when pressure is released. Experimental pressures achieved on hydrogen have been more than an order of magnitude higher than the predicted transition pressure and yet it remains an insulator.<p>So, both (1) unobtainium, and (2) merely hypothesized that storage <i>might</i> not require a container forged from another isotope of unobtainium. With insta-death still a <i>very</i> plausible risk if you get anywhere near a substantial quantity of it.<p>Sounds like the sort of technology that you should try to trick your worst enemy into working hard to perfect. At their secret research base, on the far side of planet Soveryfarawayfromme.