Changing of the lattice parameter with boron or carbon content x in nonstoichiometric perovskite-type YRh₃B_x, YRh₃C_x, and YRh₃B_xC_1-x compounds

Polycrystalline samples of YRh₃B_x, YRh₃C_x and YRh₃B_xC_1-x have been synthesized by arc melting method to clarify the relationship between the lattice parameter and boron or carbon content. All the obtained perovskite-type compounds have cubic structure (space group: Pm3m, Z=1). Perovskite-type YRh₃B_x exists in the range 0.444≤x≤ 1.0. Lattice parameter a in YRh₃B_x depends on x, and varies from 0.40944(6) nm (x=0.444) to 0.41675(5) nm (x=1.0). Perovskite-type YRh₃C_x also exists in the above range of x. Its lattice parameter a varies from 0.40855 (5) nm (x=0.444) to 0.41262 (4) nm (x=1.0). The packing mode of the boron and carbon in the host lattice of YRh₃ are very similar; the value of the lattice parameter a increases with increasing the amount of interstitial atoms of boron or carbon, x. In the case of solid solution perovskite-type YRh₃B_xC_1-x, lattice parameter a also depends on x, with being 0.41428(6)nm (x=0.25), 0.41462(5)nm (x=0.5) and 0.41506(5)nm (x=0.75); the a vs. the x does not follow the linear function.