stibine - Preparation and properties, Uses, Safety, Toxicology

SbH₃. A highly poisonous gas formed by the reduction of antimony compounds.

Stibine, also called stibane or antimony trihydride, is SbH3.

Preparation and properties

SbH3 is generally prepated by the reaction of Sb equivalents:↑ 

2 Sb2O3 + 3 LiAlH4 → 4 SbH3 + 1.5 Li2O + 1.5 Al2O3 SbCl3 + 3/4 NaBH4 → SbH3 + 0.75 NaCl + 0.75 BCl3

Alternatively, sources of Sb3− react with protonic reagents (even water) to also produce this unstable gas:

Na3Sb + 3 H2O → SbH3 + 3 NaOH

The chemical properties of SbH3 resemble those for AsH3. AsH3, H2Te, SnH4), SbH3 is unstable with respect to its elements. The gas decomposes slowly at room temperature but rapidly at 200°C:

2 SbH3 → 3 H2 + 2 Sb

The decomposition is autocatalytic and can be explosive.

SbH3 is readily oxidized by O2 or even air:

2 SbH3 + 3 O2 → Sb2O3 + 3 H2O

SbH3 exhibits no basicity, but it can be deprotonated:

SbH3 + NaNH2 → NaSbH2 + NH3

Uses

Stibine is used in the semiconductor industry to dope small quantities of antimony via the process of chemical vapour deposition (CVD). Reports claim the use of SbH3 as a fumigant but its instability and awkward preparation contrast with the more conventional fumigant PH3.

Safety

SbH3 is an unstable flammable gas. Fortunately, SbH3 is so unstable that it is rarely encountered.

Toxicology

The toxicity of stibine is distinct from that of other antimony compounds, but similar to that of arsine.↑