(Gr. Selen, moon) Discovered by Berzelius in 1817. Found in rare minerals, remains of processed copper sulfide ores and electrolytic copper refineries.
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seven allotropic forms, two forms being vitreous ( glass-like) and gray* being the most stable form, six isotopes, resembles sulfur, can convert light to electricity, can convert a.c. current to d.c. current, compounds are generally extremely toxic
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photocells, photography, solar photocells, photography, rectifiers, semiconductors, copiers, decolorize glass, photographic toner, additive to stainless steel