Effect of hydrogenation on the crystal structure of La2Pd2In

The paper is focusing on the modification of the crystal lattice upon the hydrogenation of La2Pd2In and hydrogen desorption from La2Pd2In hydrides. The synthesis at 1 bar of hydrogen produces a crystalline hydride with 1.5 H atoms per formula unit and the volume expansion of ΔV/V = 6.0%. The synthesis at 10 and 100 bar H2 pressures leads to an amorphous state and with 4 + δ H atoms/f.u. The uptake of hydrogen leads to the decrease of the Debye temperature of La2Pd2In and modification of the optical phonon spectrum.

Research highlights▶ La2Pd2In hydride is crystalline with 1.5 H atoms per formula unit and amorphous at 4 H atoms/f.u. ▶ Volume expansion of La2Pd2In due to hydrogenation reaches 6.0% (or +4.9 Å3/H atom) and is anisotropic. ▶ Hydrogenation “softens” the lattice of La2Pd2In.