Sc2In-based solid solutions in the Sc-Fe-In and Sc-Au-In systems

Phase analytical studies in the scandium-rich parts of the Sc-T-In systems (T = Fe, Au) revealed the formation of small areas of solid solutions Sc2−x Fe x In and Sc2Au x In1−x that are derived from the binary Ni2In-type phase Sc2In, space group P63/mmc. The samples were synthesized from the elements in sealed tantalum ampoules in an induction furnace. The structures of Sc1.88Fe0.12In (a = 498.37(6), c = 630.94(8) pm, wR2 = 0.0603, 124 F 2 values, nine variables), Sc2Au0.37In0.63 (a = 494.65(5), c = 632.42(6) pm, wR2 = 0.0639, 123 F 2 values, nine variables) and Sc2Au0.22In0.78 (a = 496.09(3), c = 628.29(4) pm, wR2 = 0.0331, 124 F 2 values, nine variables) were refined from single-crystal diffractometer data. Sc1.88Fe0.12In shows Sc/Fe mixing on Wyckoff position 2a, while gold is substituted for indium on site 2c. Analyses of the reciprocal space gave no hint for superstructure formation, and the three refinements show slightly enhanced U 33 displacement parameters for the 2d scandium sites which react on the mixed occupancies.