Synthesis and Structural Relationship of the Ternary Indides Sc3Ni2.10(5)In3.60(5), Sc3Ni2.14(2)In3.76(2), ScPd0.981(2)In and Sc3Rh1.594(9)In4

Abstract

The ternary scandium transition metal indides Sc3Ni2.10(5)In3.60(5), Sc3 Ni2.14(2)In3.76(2), ScPd0.981(2)In, and Sc3Rh1.594(9)In4 have been synthesized from the elements in glassy carbon crucibles in a high frequency furnace or by arc-melting. They have been investigated by X-ray powder diffraction and the structures refined on the basis of single crystal diffractometer data: Lu3Co1.87In4 type, P6̄, a = 745.7(1), c = 342.85(7) pm, wR2 = 0.0689, 545 F2, 24 parameters for Sc3Ni2.10(5)In3.60(5), a = 753.63(7), c = 344.3(1) pm, wR2 = 0.0362, 792 F2, 22 parameters for Sc3Ni2.14(2)In3.76(2), P6̄2m, ZrNiAl type, a = 764.1(2), c = 345.90(8) pm, wR2 = 0.0333, 326 F2, 15 parameters for ScPd0.981(2)In, and P6̄, a = 769.4(1), c = 684.1(1) pm, wR2 = 0.0526, 1097 F2, 35 parameters for the new structure type Sc3Rh1.594(9)In4. In the three structure types the scandium atoms build trigonal prisms. The latter are filled exclusively by palladium atoms in ScPd0.981(2)In, while transition metal and indium atoms fill these sites in the other three structures. The different coloring of the trigonal prismatic sites leads to a symmetry reduction for the structures of Sc3Ni2.10(5)In3.76(5), Sc3Ni2.14(2)In3.76(2) and Sc3Rh1.594(9)In4. The structural relationship is described on the basis of a group-subgroup scheme. Chemical bonding in these intermetallics is briefly discussed.