Rietveld refinement of the A3B (D019) and A2B (B82) phases in Ti–Sn and Ti–Ga alloys

The structures of A₃B (D0₁₉) and A₂B (B8₂) phases have been investigated using Rietveld refinement of XRD data. The analyzed chemistry of individual phases has been used to determine the site occupancy of initial models. The shifts in Ti atoms corresponding to 6(h) Wyckoff positions have been calculated in both the Ti₃Sn and Ti₃Ga phases. This is related to the presence of symmetry elements in D0₁₉ structure which in turn allows local shift due to different site occupancies resulting in different potentials. The nature of atomic shift is opposite in Ti₃Sn and Ti₃Ga phases. The site occupancy patterns of A₃B (Ti₃Sn, Ti₃Ga) and A₂B (Ti₂Sn and Ti₂Ga) are different due to unlike chemical compositions.