Reaction of samarium with acids
Samarium dissolves readily in dilute sulphuric acid, forming a yellow solution of Sm(III) ions and hydrogen gas, H2.
2 Sm(s) + 3 H2SO4(aq) 2 Sm3+(aq) + 3 SO42−(aq) + 3 H2(g)
Reaction of samarium with air
Samarium reacts slowly with oxygen, O2, tarnishing the surface, under normal conditions. Samarium burns readily, forming Sm(III) oxide, Sm2O3:
4 Sm(s) + 3 O2(g) 2 Sm2O3(s)
Reaction of samarium with halogens
Samarium reacts with the halogens, forming the corresponding samarium(III) halides:
2 Sm(s) + 3 F2(g) SmF3(s) [white]
2 Sm(s) + 3 Cl2(g) SmCl3(s) [yellow]
2 Sm(s) + 3 Br2(g) SmBr3(s) [yellow]
2 Sm(s) + 3 I2(g) SmI3(s) [orange]
Reaction of samarium with water
Samarium reacts slowly with cold water, and quickly with hot water, forming samarium hydroxide, Sm(OH)3, and hydrogen gas, H2.
2 Sm(s) + 6 H2O(l) 2 Sm(OH)3(aq) + 3 H2(g)