Beryllium arsenide should have the molecular formula
of Be3As2 and the molecular weight of 176.8801 g/mol.
However, this is a doubtful compound that has never
been prepared. Be melts at 1287 °C and the reaction at
that temperature apparently does not occur:
The reason for this is not clear but may lie in the
difference in atomic radii of the two species
(Be = 1.05 ? ; As= 1.15 ? ± 10%).