What is "hydrogen selenide"

alt. (context chemistry English) the hydride of selenium, H₂Se; it is a toxic, inflammable gas, having properties similar to those of hydrogen sulfide n. (context chemistry English) the hydride of selenium, H₂Se; it is a toxic, inflammable gas, having properties similar to those of hydrogen sulfide

Hydrogen selenide is an inorganic compound with the formula HSe. It is a hydrogen chalcogenide, and the simplest (and virtually the only) hydride of selenium. HSe is a colorless, flammable gas under standard conditions. It is the most toxic selenium compound with an exposure limit of 0.05 ppm over an 8-hour period. Even at extremely low concentrations, this compound has a very irritating smell resembling that of decayed horseradish or 'leaking gas', but smells of rotten eggs at higher concentrations.