Samarium: reactions of elements

Reaction of samarium with air

Samarium metal tarnishes slowly in air and burns readily to form samarium (III) oxide, Sm2O3.

4Sm + 3O2 → 2Sm2O3

Reaction of samarium with water

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

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

Reaction of samarium with the halogens

Samarium metal reacts with all the halogens to form samarium(III) halides. So, it reacts with fluorine, F2, chlorine, Cl2, bromine, I2, and iodine, I2, to form respectively samarium(III) bromide, SmF3, samarium(III) chloride, SmCl3, samarium(III) bromide, SmBr3, and samarium(III) iodide, SmI3.

2Sm(s) + 3F2(g) → 2SmF3(s) [white]

2Sm(s) + 3Cl2(g) → 2SmCl3(s) [yellow]

2Sm(s) + 3Br2(g) → 2SmBr3(s) [yellow]

2Sm(s) + 3I2(g) → 2SmI3(s) [orange]

Reaction of samarium with acids

Samarium metal dissolves readily in dilute sulphuric acid to form solutions containing the yellow aquated Sm(III) ion together with hydrogen gas, H2. It is quite likely that Sm3+(aq) exists as largely the complex ion [Sm(OH2)9]3+

2Sm(s) + 3H2SO4(aq) → 2Sm3+(aq) + 3SO42-(aq) + 3H2(g)

Reaction of samarium with bases

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