Lu26T17-xIn x (T = Rh, Ir, Pt) - first indium intermetallics with Sm26Co11Ga6-type structure

Several Lu26T17-xIn x (T = Rh, Ir, Pt) phases with varying x values were obtained by induction-melting reactions of the elements in sealed tantalum ampoules. All samples were characterized through their X-ray powder diffraction patterns. These compounds crystallize with the tetragonal Sm26Co11Ga6-type structure, space group P4/mbm and Z = 2. The structure of Lu26Pt7.55In9.45 has been refined from single-crystal X-ray diffractometer data: a = 1165.32(5), c = 1547.46(6) pm, wR2 = 0.0895, 2173 F-2 values and 70 variables. The Lu26T17-xIn x phases are the first indium representatives of the Sm26Co11Ga6 type. They belong to the n = 4 members of Parthe's A(5n+6)B(3n+5) series, which show different stacking sequences of square prisms and antiprisms. Lu26Pt7.55In9.45 as a lutetium-rich intermetallic compound exhibits a broader range of shorter Lu-Lu distances (341-375 pm). Temperature dependent magnetic susceptibility measurements show Pauli paramagnetism for Lu26Ir8.5In8.5 and Lu26Rh7In10 with room temperature values of the magnetic susceptibility of chi = 1.53 x 10(-3) emu mol(-1) for Lu26Rh7In10 and chi = 6.54 x 10(-4) emu mol(-1) for Lu26Ir8.5In8.5.