Hydrogenation of Dy₂Ni₂In and Al- and Ga-substituted derivatives

Chem. Met. Alloys 16 (2023) 7-13

Khrystyna MILIYANCHUK, Ladislav HAVELA, Silvie MAŠKOVÁ-ĆERNÁ, Roman GLADYSHEVSKII

https://doi.org/10.30970/cma16.0429

Hydrogenation properties of the compounds Dy₂Ni₂In (Mn₂AlB₂ structure type, Pearson symbol oS10, space group Cmmm) and Dy₂Ni₂In_0.8X_0.2 (X = Al, Ga) (Mo₂FeB₂ structure type, Pearson symbol tP10, space group P4/mbm) were studied at room temperature under hydrogen pressures below ambient. Hydrides of compositions Dy₂Ni₂InH_4.5, Dy₂Ni₂In_0.8Al_0.2H_4.2, and Dy₂Ni₂In_0.8Ga_0.2H_3.7 were synthesized. In all cases, the arrangement of the metal atoms was preserved after hydrogenation. Hydrogenation resulted in anisotropic lattice modification, which prevailed in one direction (along the a-axis) for the Mn₂AlB₂-type compound and in a plane (ab-plane) for the Mo₂FeB₂-type compounds. The role of individual structure fragments in the hydrogenation process is discussed.

Hydrogenation curves for Dy₂Ni₂In_0.8Al_0.2 (p(H₂) = 850 mbar) and Dy₂Ni₂In_0.8Ga_0.2 (p(H₂) = 870 mbar) at room temperature.

Keywords

Intermetallic / Hydride / X-ray diffraction / Crystal structure