Ternary rare earth (R) alloys occurring in RAu2-RGa2 sections

Ternary alloys of the rare earths with gold and gallium, at the stoichiometric ratio 1:0.5:1.5, were synthesised and structurally determined. New compounds were identified for R=Nd, Sm, Gd, Tb, Dy, Ho Er, Y and their crystal structures were found to be related to the hexagonal CaIn2 type. A homogeneous alloy was obtained for Yb too, and was found to crystallise in the orthorhombic oI12-CeCu2 type structure. The stability composition range of CaIn2 type was analysed in the GdAu2−xGax system: the CaIn2 type phase was found to exist for x values ranging between 1.4 and 1.55. For higher and lower x values, phases crystallising in the hP3-AlB2 and oI12-CeCu2 type structure, respectively, were observed.