STRUCTURAL STUDY OF VANADIUM SUBSTITUTED Mo₂NiB₂

Abstract

Vanadium substituted Mo_2–xNi_1–xV_2xB₂ (x = 0 and 0.45) was prepared by reaction boronizing sintering and investigated using X-ray powder diffraction. Structure of Vanadium substituted Mo_2–xNi_1–xV_2xB₂ was determined using the Rietveld method. The results show that the crystal structure of vanadium substituted Mo₂NiB₂ has changed from orthorhombic to tetragonal. The crystal structure of Mo₂NiB₂ belongs to the structure type W₂CoB₂ with space group Immm (No. 71). The unit-cell lattice parameters are a = 7.0914(2) Å, b = 4.5639(9) Å, c = 3.1787(8) Å. The reliability factor for the refinement is R_p = 6.74% and R_wp = 8.52%. The crystal structure of vanadium substituted Mo₂NiB₂ belongs to space group P4/mbm (No. 127). The lattice parameters are a = b = 5.8244(5) Å, c = 3.1239(6) Å. The reliability factor is R_p = 5.69% and R_wp = 7.41%.