|
SELENIUM
(Se)
GENERAL
PROPERTIES
|
Symbol:
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Se
|
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Atomic
Number:
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34
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Atomic
Weight:
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78.96
|
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Density:
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4.79
gm/cc
|
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Melting
Point:
|
217
oC
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Boiling
Point:
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684.9
oC
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|
Thermal
Conductivity:
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0.00519
W/cm/oK
@ 298.2 oK
|
|
Electrical
Resistivity:
|
106
microhm-cm
@ 0 oC
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|
Electronegativity:
|
2.4
Paulings
|
|
Specific
Heat:
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0.767
Cal/g/oK
@ 25 oC
|
|
Heat
of Vaporization:
|
3.34
K-cal/gm atom at 684.9 oC
|
|
Heat
of Fusion:
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1.22
Cal/gm mole
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MATERIAL
OVERVIEW
Characteristics:
Amorphous red powder, becoming black on standing and
crystalline on heating; vitreous and colloidal forms
may be prepared. Amorphous form softens at 40 °C and
melts at 217 °C. Crystalline selenium is a p-type
semiconductor. Electrically, it acts as a rectifier,
and has marked photoconductive and photovoltaic action
(converts radiant to electrical energy). The
electrical conductivity increases with increasing
light irradiation. Soluble in concentrated nitric acid
and in (liquid form) common alkalies. Forms binary
alloys with silver, copper, zinc, lead, etc. Low
toxicity. A necessary nutritional factor for animals.
TYPICAL
ANALYSES
Impurities
in ppm
|
Material
/ Purity:
|
5N
|
|
As
|
<1
|
|
Cu
|
<1
|
|
Te
|
<1
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POWDER, SHOT, PELLETS, & INGOT
|
Material
|
Purity
|
|
Selenium
Shot 1-3mm or 1-5mm
|
5N
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Selenium
Pieces 5mm and Down
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5N
|
|
Selenium
Powder-200 Mesh
|
2N7
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Selenium
Powder-325 Mesh
|
2N7
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Powder,
shot, pellets, and ingots are packaged to order and
sold by the gram or kilogram.
COMPOUNDS
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Material
|
Purity
|
|
Selenium
Bromide SeBr4
8 –Mesh
|
2N5
|
|
Selenium
Chloride SeCl4
8
–Mesh
|
2N8
|
|
Selenium
Oxide SeO2
-20
Mesh
|
2N5,
5N
|
|
Selenium
Oxybromide SeOBr2
-8 Mesh
|
2N5
|
Compounds
are packaged to order and sold by the gram or
kilogram.
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 |
