As a quite unique case a high-temperature modification was previously described for the well-known MoSi2. A detailed reinvestigation, however, proves that even minute amounts of beryllium trigger the formation of a hexagonal CrSi2-type phase rather than the established tetragonal prototype. This ternary MoSi2?xBex is stable at ambient conditions and very likely resembles the high-temperature polymorph of MoSi2. With the help of powder X-ray diffraction, electron backscatter diffraction and energy-dispersive X-ray spectroscopy analyses it was concluded that beryllium replaces silicon atoms in the crystal structure, and that the Be/Si network may contain vacancies.
NSTL
Elsevier
