In metallic hydrides, hydrogen is adsorbed as `H`-atom. Due to inclusion of hydrogen atoms, the metal lattice expands and thus the stabilityof metal hydride decreases. Therefore, when the metallic hydride is heated, it decomposes to form dihydrogen and very finely divided metal. The dihydrogen thus evolved, can be used as a fuel. Hence, transition metals or their alloys can be used to store and transport dihydrogen to used as fuel. This is known as hydrogen economy.
