Atomic Number: 34

Atomic Weight: 78.971

Melting Point: 493.65 K (220.5°C or 428.9°F)

Boiling Point: 958 K (685°C or 1265°F)

Density: 4.809 grams per cubic centimeter

Phase at Room Temperature: Solid

Element Classification: Non-metal

Period Number: 4

Group Number: 16

Group Name: Chalcogen

Selenium isotopes are mainly used for the production of medical and industrial radioisotopes. Se-77 and Se-78 are used for the production of the therapeutic radioisotope Br-77. Se-80 is used for the production of the medical radioisotope Br-80m. Se-74 is used for the production of Se-75 which is used as a source in gamma radiography. Se-76 can be used for the production of the medical isotopes Br-75 and Br-76. Se-82 has been used to study double beta decay. Most of the Selenium isotopes have been used in studies into the role of Selenium as an essential nutrient.