Preparation and Crystal Structures of some Binary Pnictides of Scandium,Zirconium, and Hafnium: Sc5Bi3, ZrBi, α‐HfSb,HfBi, HfBi2, and the Compound Zr5Bi3X1–x,Possibly Stabilized by an Impurity (X)

The title compounds were prepared by reaction of the elemental components. Of these Sc₅Bi₃ is a new compound. Its orthorhombic β‐Yb₅Sb₃ type crystal structure was determined from single‐crystal X‐ray data: Pnma, a = 1124.4(1) pm, b = 888.6(1) pm, c = 777.2(1) pm, R = 0.024 for 1140 structure factors and 44 variable parameters. For the other compounds we have established the crystal structures. ZrBi has ZrSb type structure with a noticeable homogeneity range. This structure type was also found for the low temperature (α) form of HfSb and for HfBi. For α‐HfSb this structure was refined from single‐crystal X‐ray data: Cmcm, a = 377.07(4) pm, b = 1034.7(1) pm, c = 1388.7(1) pm, R = 0.043 for 432 F values and 22 variables. HfBi₂ has TiAs₂ type structure: Pnnm, a = 1014.2(2) pm, b = 1563.9(3) pm, c = 396.7(1) pm. The structure was refined from single‐crystal data to a residual of R = 0.074 for 1038 F values and 40 variables. In addition, a zirconium bismuthide, possibly stabilized by light impurity elements X and crystallizing with the hexagonal Mo₅Si₃C_1–x type structure, was observed: Zr₅Bi₃X_1–x, a = 873.51(6) pm, c = 599.08(5) pm. The positions of the heavy atoms of this structure were refined from X‐ray powder film data. Various aspects of impurity stabilization of intermetallics are discussed.