Yttrium

Yttrium metal dissolves readily in dilute hydrochloric acid, forming aquated Y(III) ions and hydrogen gas, H₂.

2 Y(s) + 6 HCl(aq) 2 Y³⁺(aq) + 6 Cl⁻(aq) + 3 H₂(g)

Yttrium tarnishes slowly in air and burns readily, forming yttrium (III) oxide, Y₂O₃

4 Y(s) + 3 O₂(g) 2 Y₂O₃(s)

Yttrium reacts with all the halogens, forming yttrium(III) halides.

2 Y(s) + 3 F₂(g) 2 YF₃(s)
2 Y(s) + 3 Cl₂(g) 2 YCl₃(s)
2 Y(s) + 3 Br₂(g) 2 YBr₃(s)
2 Y(s) + 3 I₂(g) 2 YI₃(s)

Finely divided, or heated, yttrium dissolves in water, forming Y(III) ions and hydrogen gas, H₂.

2 Y(s) + 6 H₂O(g) 2 Y³⁺(aq) + 6 OH^-(aq) + 3 H₂(g)