RE ₄ Al ₁₃ Pt ₉ —New Representatives in the RE –Al–Pt System with the Ho ₄ Ge ₉ Ir ₁₃ ‐Type Structure ( RE = Y, La‐Nd, Sm, Gd‐Dy)

Of the RE 4 Al 13 Pt 9 series, the RE = Ce, Pr, and Eu representatives were previously reported. In this work we extend the series to RE = Y, La‐Nd, Sm, Gd‐Dy. All samples were investigated by powder X‐ray diffraction, but only Nd 4 Al 13 Pt 9 could be obtained as an X‐ray pure sample. In the other cases, often Al 3 Pt 2 was discovered as a trace side phase. Single crystal X‐ray studies on Nd 4 Al 13 Pt 9 confirmed the isotypism with the previously reported members in the orthorhombic Ho 4 Ir 13 Ge 9 type structure (space group Pmmn ). Magnetization studies were conducted on the La, Nd, Tb, and Dy samples, indicating Pauli paramagnetism for La 4 Al 13 Pt 9 and antiferromagnetic ordering at T N = 8.4(1) K for Nd, 32.6(1) K for Tb, and 15.2(1) K for Dy. The bonding was studied by quantum‐chemical methods on Y 4 Al 13 Pt 9 .