Rare-earth rich indides RE8CoIn3 (RE = Y, Dy–Tm, Lu)

New ternary indides RE8CoIn3 (RE = Y, Dy–Tm, Lu) have been prepared by arc-melting and subsequent annealing at T = 870 K. The crystal structures have been studied using X-ray powder diffraction. The RE8CoIn3 indides are isotypic with Pr8CoGa3, space group P63mc, Pearson code hP24: a = 10.3678(2), c = 7.0069(2) Å for Y8CoIn3; a = 10.3370(4), c = 6.9246(3) Å for Dy8CoIn3; a = 10.2856(2), c = 6.9030(2) Å for Ho8CoIn3; a = 10.2374(2), c = 6.8759(2) Å for Er8CoIn3; a = 10.1863(2), c = 6.8461(2) Å for Tm8CoIn3; a = 10.1168(4), c = 6.7977(4) Å for Lu8CoIn3. The coordination polyhedra of the RE atoms have 12-, 13- and 14-vertices. The polyhedron around the Co atom is an octahedron with one additional atom, and around the In atoms it is a strongly distorted trigonal prism with five additional atoms.