Reaction of erbium with acids
Erbium dissolves readily in dilute sulphuric acid, forming Er(III) ions and hydrogen gas, H2. The solution is yellow and is most likely the complex [Er(H2O)9]3+.
2 Er(s) + 3 H2SO4(aq) 2 Er3+(aq) + 3 SO42−(aq) + 3 H2(g)
Reaction of erbium with air
Erbium tarnishes slowly in air, and burns readily, forming erbium(III) oxide, Er2O3.
4 Er(s) + 3 O2(g) 2 Er2O3(s)
Reaction of erbium with halogens
Erbium reacts with all the halogens, forming the corresponding erbium(III) halides.
2 Er(s) + 3 F2(g) 2 ErF3(s) [pink]
2 Er(s) + 3 Cl2(g) 2 ErCl3(s) [violet]
2 Er(s) + 3 Br2(g) 2 ErBr3(s) [violet]
2 Er(s) + 3 I2(g) 2 ErI3(s) [violet]
Reaction of erbium with water
Erbium reacts slowly with cold water, and quickly with hot water, forming erbium hydroxide, Er(OH)3, and hydrogen gas (H2).
2 Er(s) + 6 H2O(g) 2 Er(OH)3(aq) + 3 H2(g)