Bismuth iodo-bromo complex
In experiment 2, it is shown that bismuth forms a mixed-halogen complex with chloride and iodide. A similar complex can also be made with bromide and iodide. This is done in a similar way, by using sodium bromide or potassium bromide instead of sodium chloride.
When potassium bromide is added to a precipitate of bismuth iodide, then the precipitate dissolves and a clear yellow liquid is obtained. This yellow liquid very closely resembles the liquid, obtained after adding sodium chloride to a precipitate of bismuth iodide. The only difference is that the liquid has a slightly more orange hue.
The two pictures below show two solutions of comparable concentrations of bismuth. The iodo-chloro complex of bismuth (at the left) and the iodo-bromo complex (at the right).
