Scandium-rich ternary coloring variants of the cubic Ag7+xMg26–x type

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.

The ternary system Sc–Co–In at 870 K: the isothermal section and the crystal structures of the compounds

The isothermal section of the Sc–Co–In system at T = 870 K has been constructed using X-ray powder diffraction and SEM/EDX data. At the studied temperature, nine ternary compounds are formed: Sc50Co12.5In3.5 (Ag7+x Mg24−x -type structure, space group Fm 3 ‾ $\overline{3}$ , a = 17.7411 Å), Sc14Co3.10In2.59 (Lu14Co3In3 type, P42/nmc, a = 8.8913, c = 21.387 Å), Sc6Co2.18In0.82 (Ho6Co2Ga type, Immm, a = 8.867, b = 8.780, c = 9.321 Å), Sc2CoIn (Pt2ZnCd type, P4/mmm, a = 3.2887, c = 7.1642 Å), Sc11Co4In9 (Nd11Pd4In9 type, Cmmm, a = 13.836, b = 20.758, c = 3.351 Å), Sc5Co2In4 (Lu5Ni2In4 type, Pbam, a = 17.3400, b = 7.5940, c = 3.3128 Å), Sc3Co1.64In4 (Lu3Co2−x In4 type, P 6 ‾ $\overline{6}$ , a = 7.6702, c = 3.3595 Å), Sc10Co9In20 (Ho10Ni9In20 type, P4/nmm, a = 12.8331, c = 9.0226 Å), Sc0.5In0.5Co2 (ternary non-centrosymmetric derivative of the Laves phase MgNi2, P63 mc, a = 4.8910, c = 16.0166 Å, with a homogeneity range from 12.3 to 16.7 at% of indium). The cubic phase ScCo4In (MgCu4Sn type, F 4 ‾ $\overline{4}$ 3m, a = 6.9230(8) Å) is evidently present in the cast samples and disappears after the annealing procedure. A Sc/In substitution was observed for the solid solution Sc1−x In x Co2 (x = 0–0.26) with the structure of the cubic Laves phase (MgCu2 type) and also for the hexagonal Sc0.5In0.5Co2-type phase.

Scandium–copper–indides deriving from the ZrNiAl and MnCu2Al type structures

Phase analytical studies in the Sc–Cu–In system led to samples of the solid solutions ScCu1–x–y In1+x and ScCu2–x In which were studied by X-ray powder diffraction. At room temperature the compounds ScCu1–x–y In1+x crystallize with the ZrNiAl type, space group P 6 ‾ $\overline{6}$ 2m. Exemplarily, the structure of ScCu0.76In1.17 was refined from single crystal X-ray diffractometer data, revealing strong anisotropic displacements for the scandium atoms and a mixed occupied Cu/In site. Superstructure formation is observed at low temperatures. The ScCu0.78In1.14 and ScCu0.76In1.16 structures were refined from diffraction data recorded at 90 K. Both compounds adopt the HfRhSn type, space group P 6 ‾ $\overline{6}$ 2c, a klassengleiche subgroup of index 2; doubling of the subcell c axis. The Cu/In filled trigonal Sc6 prisms are strongly distorted in the superstructure, resulting from pairwise dislocation of the Cu/In atoms from ideal positions within an equidistant chain to shorter (311.0 pm) and longer (392.8 pm) Cu/In–Cu/In distances. Single crystal data of the Heusler phases ScCu1.95In and ScCu1.94In show small degrees of copper vacancies.

Intermetallic phases in the Sc–Ir–In system – synthesis and structure of Sc1.024Ir2In0.976 and Sc3Ir1.467In4

The intermetallic scandium compounds Sc1.024Ir2In0.976 and Sc3Ir1.467In4 were synthesized by reactions of the elements in sealed tantalum ampoules at high temperature followed by annealing for crystal growth. Both structures were refined from single-crystal X-ray diffractometer data: MnCu2Al type, F m 3 ‾ m $Fm‾{3}m$ , a = 639.97(19) pm, wR2 = 0.0376, 41 F 2 values, seven variables for Sc1.024Ir2In0.976 and P 6 ‾ $P‾{6}$ , a = 769.99(5), c = 684.71(4) pm, wR2 = 0.0371, 967 F 2 values, 33 variables for Sc3Ir1.467In4. Sc1.024Ir2In0.976 is a new Heusler phase with a small homogeneity range due to Sc/In and In/Sc mixing. The structure of Sc3Ir1.467In4 is closely related to that of Sc3Rh1.594In4 and belongs to the large family of ZrNiAl superstructures. The striking structural motif is the ordered stacking of empty In6 and filled Ir@In6 prisms with Ir–In distances of 269 pm.