Bismuthine

Bismuthine
IUPAC name

bismuthane
Other names

bismuth trihydride
hydrogen bismuthide
Identifiers
CAS number 18288-22-7
PubChem 9242
Properties
Molecular formula BiH3
Molar mass 212.00 g/mol
Appearance colourless gas
Density 0.008665 g/mL (20 °C)
Boiling point

16.8 °C (extrapolated)
Structure
Molecular shape trigonal pyramidal
Related compounds
Related hydrides Ammonia
Phosphine
Arsine
Stibine
 Y (verify) (what is: Y/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Bismuthine (IUPAC name: bismuthane) 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°.[1]

The term bismuthine may also refer to a member of the family of organobismuth(III) species having the general formula BiR3, where R is an organic substituent. For example, Bi(CH3)3 is trimethylbismuthine.

Contents

Preparation and properties

BiH3 is prepared by the redistribution of methylbismuthine (BiH2Me):[2]

3 BiH2Me → 2 BiH3 + BiMe3

The required BiH2Me, which is also thermally unstable, is generated by reduction of methylbismuth dichloride, BiCl2Me with LiAlH4.[1]

As suggested by the behavior of SbH3, BiH3 is unstable with respect to its elements. The gas decomposes according to the following equation:

2 BiH3 → 3 H2 + 2 Bi (ΔHf'ogas = −278 kJ/mol)

The methodology used for detection of arsenic ("Marsh test") can also be used to detect BiH3. This test relies on the thermal decomposition of these trihydrides to the metallic mirrors of metallic As, Sb, and Bi. These deposits can be further distinguished by their distinctive solubility characteristics: As dissolves in NaOCl, Sb dissolves in ammonium polysulfide, and Bi resists both reagents.[2]

Uses and safety considerations

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

References

  1. ^ a b W. Jerzembeck, H. Bürger, L. Constantin, L. Margulès, J. Demaison, J. Breidung, W. Thiel (2002). "Bismuthine BiH3: Fact or Fiction? High-Resolution Infrared, Millimeter-Wave, and Ab Initio Studies". Angew. Chem. Int. Ed. 41 (14): 2550–2552. doi:10.1002/1521-3773(20020715)41:14<2550::AID-ANIE2550>3.0.CO;2-B. http://www3.interscience.wiley.com/journal/96516335/abstract. 
  2. ^ a b Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001.ISBN 0-12-352651-5.