Chemical reactions of the elements
Reaction of gadolinium with air
Gadolinium metal tarnishes slowly in air and burns readily to form gadolinium (III) oxide, Gd2O3.
4Gd + 3O2 → 2Gd2O3
Reaction of gadolinium with water
The silvery white metal gadolinium is quite electropositive and reacts slowly with cold water and quite quickly with hot water to form gadolinium hydroxide, Gd(OH)3, and hydrogen gas (H2).
2Gd(s) + 6H2O(g) → 2Gd(OH)3(aq) + 3H2(g)
Reaction of gadolinium with the halogens
Gadolinium metal reacts with all the halogens to form gadolinium(III) halides. So, it reacts with fluorine, F2, chlorine, Cl2, bromine, I2, and iodine, I2, to form respectively gadolinium(III) bromide, GdF3, gadolinium(III) chloride, GdCl3, gadolinium(III) bromide, GdBr3, and gadolinium(III) iodide, GdI3.
2Gd(s) + 3F2(g) → 2GdF3(s) [white]
2Gd(s) + 3Cl2(g) → 2GdCl3(s) [white]
2Gd(s) + 3Br2(g) → 2GdBr3(s) [white]
2Gd(s) + 3I2(g) → 2GdI3(s) [yellow]
Reaction of gadolinium with acids
Gadolinium metal dissolves readily in dilute sulphuric acid to form solutions containing the colourless aquated Gd(III) ion together with hydrogen gas, H2. It is quite likely that Gd3+(aq) exists as largely the complex ion [Gd(OH2)9]3+
2Gd(s) + 3H2SO4(aq) → 2Gd3+(aq) + 3SO42-(aq) + 3H2(g)
Reaction of gadolinium with bases