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Silicon

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Synonyms & Trade Names
Elemental silicon [Note: Does not occur freely in nature, but is found in silicon dioxide (silica) and in various silicates.]
CAS No.
7440-21-3
RTECS No.
VW0400000
DOT ID & Guide
1346 170(amorphous powder)
Formula
Si
Conversion
IDLH
N.D.
See: IDLH INDEX
Exposure Limits
NIOSH REL
TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)
OSHA PEL
TWA 15 mg/m3 (total) TWA 5 mg/m3 (resp) See Appendix G
Measurement Methods
NIOSH 0500 , 0600
See: NMAM or OSHA Methods
Physical Description
Black to gray, lustrous, needle-like crystals. [Note: The amorphous form is a dark-brown powder.]
Molecular Weight
28.1
Boiling Point
4271°F
Melting Point
2570°F
Solubility
Insoluble
Vapor Pressure
0 mmHg (approx)
Ionization Potential
NA
Specific Gravity
(77°F): 2.33
Flash Point
NA
Upper Explosive Limit
NA
Lower Explosive Limit
NA
Minimum Explosive Concentration
160 g/m3
Combustible Solid in powder form.
Incompatibilities & Reactivities
Chlorine, fluorine, oxidizers, calcium, cesium carbide, alkaline carbonates
Exposure Routes
inhalation, ingestion, skin and/or eye contact
Symptoms
irritation eyes, skin, upper respiratory system; cough
Target Organs
Eyes, skin, respiratory system
Personal Protection/Sanitation
(See protection codes)
Skin:No recommendation
Eyes:Prevent eye contact
Wash skin:No recommendation
Remove:No recommendation
Change:No recommendation
First Aid
(See procedures)
Eye:Irrigate immediately

Breathing:Fresh air
Swallow:Medical attention immediately
Respirator Recommendations

Not available.

Important additional information about respirator selection

See also
INTRODUCTION   ICSC CARD: 1508
Page last reviewed: October 30, 2019
Content source: National Institute for Occupational Safety and Health