Cerium: reactions of elements

Reaction of cerium with air

Cerium metal tarnishes slowly in air and burns readily to form cerium (IV) oxide, CeO2.

Ce + O2 → CeO2

Reaction of cerium with water

The silvery white metal cerium is quite electropositive and reacts slowly with cold water and quite quickly with hot water to form cerium hydroxide, Ce(OH)3, and hydrogen gas (H2).

2Ce(s) + 6H2O(g) → 2Ce(OH)3(aq) + 3H2(g)

Reaction of cerium with the halogens

Cerium metal reacts with all the halogens to form cerium(III) halides. So, it reacts with fluorine, F2, chlorine, Cl2, bromine, I2, and iodine, I2, to form respectively cerium(III) bromide, CeF3, cerium(III) chloride, CeCl3, cerium(III) bromide, CeBr3, and cerium(III) iodide, CeI3.

2Ce(s) + 3F2(g) → 2CeF3(s) [white]

2Ce(s) + 3Cl2(g) → 2CeCl3(s) [white]

2Ce(s) + 3Br2(g) → 2CeBr3(s) [white]

2Ce(s) + 3I2(g) → 2CeI3(s) [yellow]

Reaction of cerium with acids

Cerium metal dissolves readily in dilute sulphuric acid to form solutions containing the colourless aquated Ce(III) ion together with hydrogen gas, H2. It is quite likely that Ce3+(aq) exists as largely the complex ion [Ce(OH2)9]3+

2Ce(s) + 3H2SO4(aq) → 2Ce3+(aq) + 3SO42-(aq) + 3H2(g)

Reaction of cerium with bases

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