Rhodium

Rhodium does not dissolve in acids, including aqua regia.

Rhodium does not react with with oxygen, O₂, under normal conditions. If heated to 600 °C, rhodium is oxidized to Rh(III) oxide:

4 Rh(s) + 3 O₂(g) 2 Rh₂O₃(s) [dark grey]

Rhenium react with fluorine, F₂, forming rhodium(VI) fluoride, RhF₆. If heated, the hexafluoride is transformed to the tetrameric rhodium(V) fluoride, [RhF₅]₄.

Rh(s) + 3 F₂(g) RhF₆(s) [black]
4 RhF₆(s) [RhF₅]₄(s) [dark red] + 2 F₂(g)

Under dry conditions, rhodium(III) fluoride can be formed:

2 Rh(s) + 3 F₂(g) 2 RhF₆(s) [red]


Rhenium react with chlorine, Cl₂ and bromine, Br₂, forming the corresponding rhodium(III) halides:

2 Rh(s) + 3 Cl₂(g) 2 RhCl₆(s) [red]
2 Rh(s) + 3 Br₂(g) 2 RhBr₆(s) [red-brown]

Rhodium does not react with water under normal conditions.