Selenium, Elemental

CAS RN:7782-49-2

Property Summary

Boiling Point:
    685 deg C

Density Specific Gravity:
    4.39 g/cu cm (alpha form); 4.809 g/cu cm (gray selenium); 4.28 g/cu cm (vitreous selenium)

Melting Point:
    220.8 deg C (gray selenium); vitreous selenium is transformed to gray selenium at 180 deg C; alpha-form transforms to gray at temperatures above 120 deg C

Molecular Formula:

Molecular Weight:
    Atomic weight = 78.96

    Soluble in aq potassium cyanide soln, potassium sulfite soln, dilute aqueous caustic alkali soln
    Insoluble in water and alcohol
    Soluble in concentrated nitric acid.
    Soluble in carbon disulfide, 2 mg/100 mL at room temperature; soluble in ether

Vapor Pressure:
    1 Pa at 227 deg C; 10 Pa at 279 deg C; 100 Pa at 344 deg C; 1 kPa at 431 deg C; 10 kPa at 540 deg C; 100 kPa at 685 deg C

    221 mPa-S (= cP) at 220 deg C; 70 cP at 360 deg C

Find more information on this substance at: Hazardous Substances Data Bank , TOXNET , PubMed