Most common oxidation states: +3, +5

M.P. 271^o

B.P. 1560^o

Density 9.75 g/cm³

Characteristics: Hard, brittle, with a reddish cast. Rather inactive, but will dissolve in nitric acid or hot sulfuric acid.

The +3 oxidation state is the more stable one.

Aqueous ammonia reacts with bismuth(III) ion to precipitate white bismuth hydroxide:

Bi³⁺(aq) + 3NH₃(aq) + 3H₂O(aq) <==> Bi(OH)₃(s) + 3NH₄⁺(aq) 

Sodium hydroxide reacts with bismuth(III) ion to produce a precipitate of Bi(OH)₃.

Bi³⁺(aq) + 3OH^-(aq) <==> Bi(OH)₃(s)

Bi(OH)₃ does not dissolve in excess ammonia or sodium hydroxide, but does dissolve in acids:

Bi(OH)₃(s) + 3H⁺(aq) <==> Bi³⁺(aq) + 3H₂O(l)

Compounds of Bi³⁺ hydrolyze readily in dilute solutions, especially when chloride ion is present, to form a white precipitate of BiOCl:

Bi³⁺(aq) + Cl^-(aq) + H₂O(l) <==> BiOCl(s) + 2H⁺(aq)

An acid should be added to aqueous solutions of bismuth(III) salts to prevent this precipitation.

 Stannite Ion:

Stannite ion reduces bismuth hydroxide to small black particles of metallic bismuth:

2Bi(OH)₃(s) + 3Sn(OH)₄^2-(aq) <==> 2Bi(s) + 3Sn(OH)₆^2-(aq)

The solution of stannite ion must be prepared just prior to use, by treating a solution of tin(II) chloride with excess sodium hydroxide:

Sn²⁺(aq) + 2OH^-(aq) <==> Sn(OH)₂(s) (white)

Sn(OH)₂(s) + 2OH^-(aq) <==> Sn(OH)₄^2-(aq) 

 No Reaction:

Cl^-, SO₄^2-

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