New rare earth metal-rich indides RE14Ni3In3 (RE=Sc, Y, Gd–Tm, Lu)—synthesis and crystal chemistry

The rare earth–nickel–indides RE14Ni3In3 (image, Y, Gd–Tm, Lu) were synthesized from the elements by arc-melting and subsequent annealing. The compounds were investigated on the basis of X-ray powder and single crystal data: Lu14Co2In3 type, P42/nmc, image, image, image, image, 1381 F2 values, 63 variables for Sc13.89Ni3.66In2.45; image, image, image, 1741 F2 values, 64 variables for Y13.84Ni3.19In2.97; image, image, image, 1765 F2 values, 63 variables for Gd14Ni3.29In2.71; image, image, image, 1707 F2 values, 64 variables for Tb13.82Ni3.36In2.82; image, image, image, 1794 F2 values, 64 variables for Dy13.60Ni3.34In3.06; image, image, image, 1191 F2 values, 64 variables for Ho13.35Ni3.17In3.48; image, image, image, 1646 F2 values, 64 variables for Er13.53Ni3.14In3.33; image, image, image, 1611 F2 values, 64 variables for Tm13.47Ni3.28In3.25; image, image, image, 1604 F2 values, 64 variables for Tm13.80Ni3.49In2.71; and image, image, image, 1603 F2 values, 64 variables for Lu13.94Ni3.07In2.99. The RE14Ni3In3 indides show significant Ni/In mixing on the 4c In1 site. Except the gadolinium compound, the RE14Ni3In3 intermetallics also reveal RE/In mixing on the 4c RE1 site, leading to the refined compositions. Due to the high rare earth metal content, the seven crystallographically independent RE sites have between 9 and 10 nearest RE neighbors. The RE14Ni3In3 structures can be described as a complex intergrowth of rare earth-based polyhedra. Both nickel sites have a distorted trigonal-prismatic rare earth coordination. An interesting feature is the In2–In2 dumb-bell at an In2–In2 distance of 304 pm (for Gd14Ni3.29In2.71). The crystal chemical peculiarities of the RE14Ni3In3 indides are briefly discussed.