Selenium - ₃₄Se: reactions of elements

Reaction of selenium with air

Selenium burns in air to form the solid dioxide selenium(IV) oxide, SeO₂.

Se₈(s) + 8O₂(g) → 8SeO₂(s)

Reaction of selenium with water

Reaction of selenium with the halogens

Selenium reacts with fluorine, F₂, and burns to form the hexafluoride selenium(VI) fluoride.

Se₈(s) + 24F₂(g) → 8SeF₆(l) [orange]

Selenium (preferably suspended in CS₂) reacts with chlorine and bromine to form diselenium dichloride, Se₂Cl₂ and diselenium dibromide, Se₂Br₂ respectively.

Se₈ + 4Cl₂ → 4Se₂Cl₂(l) [orange]

Se₈ + 4Br₂ → 4Se₂Br₂(l) [orange]

Carefully done, selenium reacts with fluorine, F₂, at 0°C to form the tetrafluoride selenium(IV) fluoride. Selenium also reacts under controlled conditions with the other halogens chlorine, Cl₂, bromine, Br₂, and iodine, I₂, to form the respective tetrahalides selenium(IV) chlrode, selenium(IV) bromide, and selenium(IV) iodide.

Se₈(s) + 16F₂(g) → 8SeF₄(s) [colourless]

Se₈(s) + 16Cl₂(g) → 8SeCl₄(s)

Se₈(s) + 16Br₂(g) → 8SeBr₄(s)

Se₈(s) + 16I₂(g) → 8SeI₄(s)

Reaction of selenium with acids

Selenium does not react with dilute non-oxidizing acids.

Reaction of selenium with bases