Pt₅Mn₂Ge, New Platinum-Rich Intermetallic of the Rh₅Ge₃ Type: Synthesis, Crystal and Electronic Structure, and Magnetic Properties

New platinum-based intermetallic Pt₅Mn₂Ge was obtained as a bulk sample using arc-melting of the elements with subsequent high-temperature annealing. The structure of the compound was refined using full-profile Rietveld method. Pt₅Mn₂Ge is isotypic to recently discovered Pt₅Mn₂Si and crystallizes in the Rh₅Ga₂As structure type, space group Pbam, a = 5.3791(5) Å, b = 10.982(1) Å, c = 4.0201(3) Å, Z = 2, an ordered variation of the Rh₅Ge₃ structure type. DFT calculations predict Pt₅Mn₂Ge to be a metallic conductor. Magnetic measurements show that the compound has a magnetic transition below ca. 100 K, most likely attributed to ferrimagnetic ordering. This compound is only the second one reported in the Pt–Mn–Ge system.