Due to their large energy gap and hardness, beryllium
sulfides and selenides are interesting materials
for improving the lifetime of optical devices made of
other II-VI-semiconductors by forming multicombinatory
alloys, notably with ZnS or CdS.
Beryllium sulfide can
be prepared by the direct reaction of the elements,
calcined in an inert atmosphere, at a 1.0:1.05 molecular
ratio:
Be＋ S＋ heat→BeS
Beryllium does not form a polysulfide.
