Röntgen- und Neutronenbeugungsuntersuchungen der Struktur von Pt3B2

Metallographical and splat-cooling investigations were carried out on alloys with compositions between Pt 62.5 B 37.5 and Pt 49 B 51 . Pt 3 B 2 is the most boron-rich stable phase of the binary system platinum-boron. The structure of this phase is of orthorhombically distorted and partially defective anti-NiAs type, space grouP Cmcm, a=3.371 (1) A, b=5.817 (2) A and c=4.045 (1) A. Guinier photographs with CuKα 1 and CoKα 1 radiation and silicon as an internal calibration standard were used for calculation of the lattice parameters. On the other hand, neutron diffraction (λ=1.184A) was applied for the refinement of the atom positions. The structural relationship between Pt 3 B 2 and homeotypical phases is discussed