Platinum

Platinum metal does not normally react with air.

Platinum will react with F₂, Cl₂, Br₂ and I₂ forming platinum halides.

For fluorine, at mixture of platinum(VI) fluoride, PtF₆, and the tetrameric platinum(V) fluoride, (PtF₅)₄ is formed, depending on the reaction conditions. The tetrameric platinum(V) fluoride disproportionates into platinum(VI) fluoride and platinum(IV) fluoride, PtF₄:

Pt(s) + 3 F₂(g) PtF₆(s) [dark red]
4 Pt(s) + 10 F₂(g) (PtF₅)₄(s) [deep red]
(PtF₅)₄(s) PtF₆(s) + PtF₄(s) [yellow brown]


For chlorine Pt(II)chloride and Pt(IV)chloride is formed, depending on reaction conditions. Pt(II)chloride comes in two forms.

Pt(s) + Cl₂(g) PtCl₂(s) [brown black]
Pt(s) + 2 Cl₂(g) PtCl₄(s) [dark red or olive green]


For bromine and iodine, Pt(IV)halides formed.

Pt(s) + 2 Br₂(g) PtBr₄(s) [brown black]
Pt(s) + 2 I₂(g) PtI₄(s) [brown black]

Platinum does not react with hydrogen, but hydrogen can be dissolved in platinum [5].

Platinum metal does not normally react with water.