It is readily formed from the elements at 1 atmosphere at 100–200°C:[1] When the stoichiometry is close to PuH2 it has a silver appearance, but gets blacker as the hydrogen content increases, additionally the color change is associated with a reduction in conductivity.

[2] Studies of the reaction of plutonium metal with moist air at 200–350°C showed the presence of cubic plutonium hydride on the surface along with Pu2O3, PuO2 and a higher oxide identified by X-ray diffraction and X-ray photoelectron spectroscopy as the mixed-valence phase PuIV3−xPuVIxO6+x.

[3] Investigation of the reaction performed without heating suggests that the reaction of Pu metal and moist air the production of PuO2 and a higher oxide along with adsorbed hydrogen, which catalytically combines with O2 to form water.

[4] Like the free metal, plutonium dihydride is pyrophoric.

On the surface of hydrided plutonium, it acts as a catalyst for the oxidation of the metal with consumption of both O2 and N2 from air.