Bismuthine


Bismuthine is the chemical compound with the formula BiH3. As the heaviest analogue of ammonia, BiH3 is unstable, decomposing to bismuth metal well below 0 °C. This compound adopts the expected pyramidal structure with H-Bi-H angles of around 90°.
The term bismuthine may also refer to a member of the family of organobismuth species having the general formula, where R is an organic substituent. For example, Bi3 is trimethylbismuthine.

Preparation and properties

BiH3 is prepared by the redistribution of methylbismuthine :
The required BiH2Me, which is also thermally unstable, is generated by reduction of methylbismuth dichloride, BiCl2Me with LiAlH4.
As suggested by the behavior of SbH3, BiH3 is unstable and decomposes to its constituent elements according to the following equation:
The methodology used for detection of arsenic can also be used to detect BiH3. This test relies on the thermal decomposition of these trihydrides to the metallic mirrors of reduced As, Sb, and Bi. These deposits can be further distinguished by their distinctive solubility characteristics: arsenic dissolves in NaOCl, antimony dissolves in ammonium polysulfide, and bismuth resists both reagents.

Uses and safety considerations

Bismuthine is highly toxic.
The low stability of BiH3 poses significant hazards and precludes technical applications, except as an intermediary product.