Crystal structure and hydrogenation properties of the hexagonal Dy₂M₁₇ and Dy₂M₁₇C_x (M = Fe, Co, Ni; x < 0.5) compounds

Chem. Met. Alloys 7 (2014) 26-31

https://doi.org/10.30970/cma7.0264

Volodymyr LEVYTSKYY, Volodymyr BABIZHETSKYY, Oksana MYAKUSH, Bogdan KOTUR, Ihor KOVAL’CHUK

The crystal structures of the Dy₂M₁₇ (M = Fe, Co, Ni) compounds were investigated from single crystal X-ray diffraction data (Th₂Ni₁₇ type structure, space group P6₃/mmc). The Dy₂M₁₇ binaries (M = Co, Ni) dissolve limited amounts of carbon, up to 0.2 (M = Co) and 0.4 (M = Ni) at. C/f.u. The hydrogenation properties of the parent compounds and their carbides were investigated. Dy₂M₁₇ (M = Co, Ni) absorb 3.4 (M = Co) and 3.5 (M = Ni) at. H/f.u. at 5 MPa hydrogen pressure. The carbides Dy₂M₁₇C_x (M = Co, Ni) absorb 2.7 (M = Co) and 2.8 (M = Ni) at. H/f.u. The synthesized carbides, hydrides and carbohydrides preserve the crystal structure of the parent compounds.

Unit cell of ideal Dy₂M₁₇ (M = Co, Ni) with Th₂Ni₁₇-type structure.

Keywords

Hydrides / Carbides / Crystal structure / X-ray diffraction