Elemental selenium can be recovered from H2Se through a reaction with aqueous sulfur dioxide (SO2). ::2 H2Se + SO2 ⇌ 2 H2O + 2 Se + S Its decomposition is used to prepare the highly pure element.
Hydrogen selenide
Hydrogen fluoride
Vinyl chloride
Cerate
Fomite
Methylphosphonyl difluoride
Lewis lead
Sybil 