Chemical reactions of the elements
Reaction of neodymium with air
Neodymium metal tarnishes slowly in air and burns readily to form neodymium (III) oxide, Nd2O3.
4Nd + 3O2 → 2Nd2O3
Reaction of neodymium with water
The silvery white metal neodymium is quite electropositive and reacts slowly with cold water and quite quickly with hot water to form neodymium hydroxide, Nd(OH)3, and hydrogen gas (H2).
2Nd(s) + 6H2O(g) → 2Nd(OH)3(aq) + 3H2(g)
Reaction of neodymium with the halogens
Neodymium metal reacts with all the halogens to form neodymium(III) halides. So, it reacts with fluorine, F2, chlorine, Cl2, bromine, I2, and iodine, I2, to form respectively neodymium(III) bromide, NdF3, neodymium(III) chloride, NdCl3, neodymium(III) bromide, NdBr3, and neodymium(III) iodide, NdI3.
2Nd(s) + 3F2(g) → 2NdF3(s) [violet]
2Nd(s) + 3Cl2(g) → 2NdCl3(s) [mauve]
2Nd(s) + 3Br2(g) → 2NdBr3(s) [violet]
2Nd(s) + 3I2(g) → 2NdI3(s) [green]
Reaction of neodymium with acids
Neodymium metal dissolves readily in dilute sulphuric acid to form solutions containing the lilac aquated Nd(III) ion together with hydrogen gas, H2. It is quite likely that Nd3+(aq) exists as largely the complex ion [Nd(OH2)9]3+
2Nd(s) + 3H2SO4(aq) → 2Nd3+(aq) + 3SO42-(aq) + 3H2(g)
Reaction of neodymium with bases