Selenium (Se) 1, Physical character: Atomic Weight: *8.*6 Electronegative: 2.*8 Density: ρ=4.*2 g/cm3 Melting Point: mp: **7 °C Boiling Point: bp: **4.9 °C 2, Specification: High Purity Selenium: Se**5 Grade *9.**9. The content of Selenium is above *9.**9%. The total content of Ag, Al, Bi, Cd, Cu, Fe, Co, In, Mg, Ni, Pb, Sb, Te, Zn, Mn,Ca & Tl is bellow *0 ppm; Uitra Purity Selenium: Se**6 Grade *9.***9. The content of Selenium is above *9.***9%. The total content of Ag, Al, Mg, Au, Bi, Cd, Co, In, Cu, Fe, Te, Pb & Ni is bellow 1 ppm. 3, Physical Size: Virgulate, Powder. 4, Usage: It is mainly used in the preparation of the material of the selenium drum, photoelectric material, electrostatic photogragh and other materials of optical instrument.. 5, Packing: It is packed with dacron film, then covered with a sealed plastic film bag.