he valence of selenium depends on which compound it is in. Selenium is very similar to sulfur. It may have a valence of 6; example selenium hexafluoride SeF6, selenium trioxide SeO3
4; example selenium tetrafluoride SeF4, selenium dioxide SeO2
2; example selenium difluoride SeF2, selenium dichloride SeCl2
and -2; example hydrogen selenide H2Se
