Iron pentahydride FeH5 is a superhydride compound of iron and hydrogen, stable under high pressures.
Pairs of hydrogen atoms are not bonded together into molecules.
FeH5 has been made by compressing a flake of iron with hydrogen in a diamond anvil cell to a pressure of 130 GPa and heating to below 1500K.
[1] When decompressed to 66 GPa it decomposes to solid FeH3.
The unit cell is tetragonal with space group I4/mmm.