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selenium

(sə lē′nē əm)

noun

a nonmetallic chemical element with several allotropic forms, used in photoelectric devices because its electrical conductivity varies with the intensity of light: also used in rectifiers, in certain electrostatic copying processes, etc.: symbol, Se; at. no., 34

Origin: ModL: so named (1818) by Baron Jöns Jakob Berzelius < Gr selēnē, the moon (see Selene) + -ium, by analogy with tellurium, with which it was assoc. in the ore

See selenium in American Heritage Dictionary 4

noun Symbol Se

A nonmetallic element, red in powder form, black in vitreous form, and metallic gray in crystalline form, resembling sulfur and obtained primarily as a byproduct of electrolytic copper refining. It is widely used in rectifiers, as a semiconductor, and in xerography. Its photovoltaic and photoconductive actions make it useful in photocells, photographic exposure meters, and solar cells. Atomic number 34; atomic weight 78.96; melting point (of gray selenium) 217°C; boiling point (gray) 684.9°C; specific gravity (gray) 4.79; (vitreous) 4.28; valence 2, 4, or 6. See Table at element.

Origin:

Origin: Greek selēnē, moon (from selas, light, brightness)

Origin: + -ium

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