Phase equilibria in the Er-Co-In system and crystal structure of Er8CoIn3 compound

Isothermal section of the Er-Co-In system at T = 870 K was constructed by means of X-ray powder diffraction, microstructure, and EDX-analyses. Twelve ternary compounds, namely ErCoIn 5 (HoCoGa 5 -type), Er 6 Co 17.92 In 14 (Lu 6 Co 17.92 In 14 -type), ErCo 4 In (MgCu 4 Sn-type), Er 2 CoIn 8 (Ho 2 CoGa 8 -type), Er 10 Co 9 In 20 (Ho 10 Ni 9 In 20 -type), Er 3 Co 1.87 In 4 (Lu 3 Co 1.87 In 4 -type), ErCoIn, Er 11 Co 4 In 9 (Nd 11 Pd 4 In 9 -type), Er 11 Co 3 In 6 , Er 8 CoIn 3 (Pr 8 CoGa 3 -type), Er 6 Co 2.19 In 0.81 (Ho 6 Co 2 Ga-type), and Er 13.83 Co 2.88 In 3.10 (Lu 14 Co 2 In 3 -type) exist in the Er-Co-In system at this temperature. The crystal structure of the Er 8 CoIn 3 compound was determined by means of X-ray powder method (Pr 8 CoGa 3 -type, P 6 3 mc space group, a = 1.02374(2) nm, c = 0.68759(2) nm). Almost none of the binary compounds dissolve the third component. The exception is the existence of the solid solution based on ErCo 3 binary compound, which dissolves up to 8 at.% of In.