Synthesis, crystal structure and properties of the plumbides AE AuPb ( AE = Ca, Sr, Ba)

The intermetallic compounds AE AuPb ( AE = Ca, Sr, Ba) were synthesized from the elements and structurally characterized as isopointal to the orthorhombic KHg 2 -type structure ( Imma , CaAuPb: a = 4.8068(9), b = 7.3795(5), c = 8.327(1) Å; SrAuPb: a = 4.9038(2), b = 7.7977(3), c = 8.4651(4) Å; BaAuPb: a = 5.0266(4), b = 8.1804(4), c = 8.6834(8) Å). Single-crystal X-ray diffraction of SrAuPb revealed mixed Au/Pb site occupancy, while isotypic CaAuPb and BaAuPb structures were obtained from powder X-ray diffraction. All three compounds exhibit metallic conductivity and weak, temperature-independent Pauli paramagnetism, consistent with nonmagnetic, delocalized electronic states. These results identify the AE AuPb series as nonmagnetic Au–Pb plumbides with mixed site occupancy and provide a basis for further exploration of spin–orbit coupling effects arising from the presence of gold and lead.