Scandium

Scandium dissolves readily in dilute hydrochloric acid, forming Sc(III) ions and hydrogen gas, H₂.

2 Sc(s) + 6 HCl(aq) 2 Sc³⁺(aq) + 6 Cl⁻(aq) + 3 H₂(g)

Scandium tarnishes in air, and burns readily, forming scandium(III) oxide, Sc₂O₃.

4 Sc(s) + 3 O₂(g) 2 Sc₂O₃(s)

Scandium reacts with the halogens, forming the corresponding Sc(III) halides

2 Sc(s) + 3 F₂(g) 2 ScF₃(s)
2 Sc(s) + 3 Cl₂(g) 2 ScCl₃(s)
2 Sc(s) + 3 Br₂(g) 2 ScBr₃(s)
2 Sc(s) + 3 I₂(g) 2 ScI₃(s)

When finely divided, or heated, scandium dissolves in water, forming Sc(III) hydroxide and hydrogen gas, H₂.

2 Sc(s) + 6 H₂O(l) 2 Sc(OH)₃(aq) + 3 H₂(g)