Synthesis and Structural Relationship of the Ternary Indides Sc₃Ni_2.10(5)In_3.60(5), Sc₃Ni_2.14(2)In_3.76(2), ScPd_0.981(2)In and Sc₃Rh_1.594(9)In₄

Abstract

The ternary scandium transition metal indides Sc 3 Ni 2.10(5) In 3.60(5) , Sc 3 Ni 2.14(2) In 3.76(2) , ScPd 0.981(2) In, and Sc 3 Rh 1.594(9) In 4 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: Lu 3 Co 1.87 In 4 type, P6̄, a = 745.7(1), c = 342.85(7) pm, wR2 = 0.0689, 545 F 2 , 24 parameters for Sc 3 Ni 2.10(5) In 3.60(5) , a = 753.63(7), c = 344.3(1) pm, wR2 = 0.0362, 792 F 2 , 22 parameters for Sc 3 Ni 2.14(2) In 3.76(2) , P6̄2m, ZrNiAl type, a = 764.1(2), c = 345.90(8) pm, wR2 = 0.0333, 326 F 2 , 15 parameters for ScPd 0.981(2) In, and P6̄, a = 769.4(1), c = 684.1(1) pm, wR2 = 0.0526, 1097 F 2 , 35 parameters for the new structure type Sc 3 Rh 1.594(9) In 4 . In the three structure types the scandium atoms build trigonal prisms. The latter are filled exclusively by palladium atoms in ScPd 0.981(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 Sc 3 Ni 2.10(5) In 3.76(5) , Sc 3 Ni 2.14(2) In 3.76(2) and Sc 3 Rh 1.594(9) In 4 . The structural relationship is described on the basis of a group-subgroup scheme. Chemical bonding in these intermetallics is briefly discussed.