Phase equilibria in the system Ce–Ni–C at 800°С in the range 0-33.3 at.% Ce and new isostructural compounds R₂Ni₅C₃ (R = Pr, Nd)

Chem. Met. Alloys 9 (2016) 34-41

https://doi.org/10.30970/cma9.0319

Mykola HEMBARA, Volodymyr LEVYTSKYY, Volodymyr BABIZHETSKYY, Bogdan KOTUR

The phase equilibria in the ternary system Ce–Ni–C at 800°C in the range 0-33.3 at.% Ce were investigated by means of X-ray diffraction and energy-dispersive spectroscopy. Three ternary, CeNiC₂, Ce₂Ni₅C₃, and Ce₂Ni₂₂C_2.75, and five binary Ce–Ni and Ce–C compounds at 800°C were confirmed. Two new isostructural ternary compounds (structure type La₂Ni₅C₃, space group P4/mbm): Pr₂Ni₅C₃ (a = 8.2888(1) Å, c = 3.95343(8) Å) and Nd₂Ni₅C₃ (a = 8.2810(2) Å, c = 3.9292(1) Å), were synthesized and their crystal structures were refined. The compounds continue the isostructural series of R₂Ni₅C₃ ternary carbides with La₂Ni₅C₃-type structure.

Unit cell content and coordination polyhedra of the atoms in the crystal structure of the R₂Ni₅C₃ ternary compounds (R = Ce, Pr, Nd) with La₂Ni₅C₃-type structure.

Keywords

Carbides / Phase equilibria / Crystal structure / Isostructural compounds