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selenium - 6 dictionary results
se⋅le⋅ni⋅um
[si-lee-nee-uh
m] 
–noun Chemistry.
| a nonmetallic element chemically resembling sulfur and tellurium, occurring in several allotropic forms, as crystalline and amorphous, and having an electrical resistance that varies under the influence of light. Symbol: Se; atomic weight: 78.96; atomic number: 34; specific gravity: (gray) 4.80 at 25°C, (red) 4.50 at 25°C. |
n
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Based on the Random House Dictionary, © Random House, Inc. 2009.
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Based on the Random House Dictionary, © Random House, Inc. 2009.
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Link To selenium
| se·le·ni·um (sĭ-lē'nē-əm) n. 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. [Greek selēnē, moon (from selas, light, brightness) + -ium.] |
The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2009 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Copyright © 2009 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Selenium
Se*le"ni*um\, n. [NL., from Gr. ??? the moon. So called because of its chemical analogy to tellurium (from L. tellus the earth), being, as it were, a companion to it.] (Chem.) A nonmetallic element of the sulphur group, and analogous to sulphur in its compounds. It is found in small quantities with sulphur and some sulphur ores, and obtained in the free state as a dark reddish powder or crystalline mass, or as a dark metallic-looking substance. It exhibits under the action of light a remarkable variation in electric conductivity, and is used in certain electric apparatus. Symbol Se. Atomic weight 78.9.
Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.
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Main Entry: se·le·ni·um
Pronunciation: s&-'lE-nE-&m
Function: noun
: a nonmetallic element that resembles sulfur and telluriumchemically, causes poisoning in range animals when ingested by eating some plants growing in soils in which it occurs in quantity, and occurs in allotropic forms of which a gray stable form varies inelectrical conductivity with the intensity of its illumination and is used in electronic devices —symbol Se; —see
Merriam-Webster's Medical Dictionary, © 2002 Merriam-Webster, Inc.
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selenium se·le·ni·um (sĭ-lē'nē-əm)
n.
Symbol Se
A nonmetallic element, with red, black, and gray allotropic forms, resembling sulfur and obtained primarily as a byproduct of electrolytic copper refining. Atomic number 34; atomic weight 78.96; melting point (of gray selenium) 221°C; boiling point (gray) 684.9°C; specific gravity (gray) 4.79; (black) 4.28; valence 2, 4, or 6.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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| selenium (sĭ-lē'nē-əm) Pronunciation Key
Symbol Se A nonmetallic element that occurs in a gray crystalline form, as a red powder, or as a black glassy material. It is highly photosensitive and can be used to convert light into electricity. Its ability to conduct electricity also increases with higher exposure to light. For these reasons selenium is used in photocopying technology, photography, and solar cells. Atomic number 34; atomic weight 78.96; melting point 217°C; boiling point 684.9°C; specific gravity (gray) 4.79; (red) 4.5; (black) 4.28; valence 2, 4, or 6. See Periodic Table. |
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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