Struktur von Schmelzen aus dem System Wismut-Antimon mittels Neutronenbeugung

Neutron diffraction work (λ = 0.695 Å) was done with molten Bi-Sb-alloys in the temperature range between 550 and 750 °C. Furthermore molten Bi was investigated at 300 °C. The interference functions show subsidiary maxima especially for alloys with higher Sb-concentrations. Evaluation yields, that the melts contain two different kinds of structure: a) The one kind shows coordination number 9 and a statistical distribution of the atoms of two components. This kind is more inetal-like. b) The other kind shows coordination number 3, consists of non-centered tetrahedra with smaller nearest neighbour distance. It shows covalent binding. In molten Sb the nearest neighbour distance amounts up to 3.16 - 3.19 Å for theo ne kind and up to 2.64 -2.78 Å fort he other kind, which yields an mean distance of 2.99 Å, which was observed. The dependence of the concentration of the statistical kind of meld, of the (Sb) -, and the (Bi) -kind from the concentration of the whole melt is given. By the model described the run of the measured mean coordination number and the mean distance versus concentration can be well explained.