X-ray diffraction was done with molten Fe 66,7 Si 33,3 and molten Fe 33,3 Si 66,7 . The coordination numbers versus the concentration lie above the connection line between the coordination numbers of the unalloyed molten elements Fe and Si, respectively, which means a tendency for microsegregation. The pair correlation function of molten Fe 66,7 Si 33,3 was modeled using the data of crystalline Fe 2 Si. At the same time, the pair correlation function of the molten alloy Fe 33,3 Si 66,7 can be modeled using the data of the corresponding crystalline alloy. Thus for molten Fe 33,3 Si 66,7 microsegregation into FeSi 2 and Si or FeSi and for molten Fe 66,7 Si 33,3 microsegregation into Fe 2 Si and Fe or FeSi exists.