Stibine is a chemical compound with the formula SbH₃. A pnictogen hydride, this colourless gas is the principal covalent hydride of antimony, and a heavy analogue of ammonia. The molecule is pyramidal with H–Sb–H angles of 91.7° and Sb–H distances of 170.7 pm (1.707 Å). This gas has an offensive smell like hydrogen sulfide (rotten eggs).

SbH₃ is generally prepared by the reaction of Sb³⁺ sources with H⁻ equivalents:

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

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

The decomposition is and can be explosive.

SbH₃ is readily oxidized by O₂ or even air:

SbH₃ exhibits no basicity, but it can be deprotonated:

Stibine is used in the semiconductor industry to dope silicon with small quantities of antimony via the process of chemical vapour deposition (CVD). It has also been used as a silicon dopant in epitaxial layers. Reports claim the use of SbH₃ as a fumigant but its instability and awkward preparation contrast with the more conventional fumigant phosphine.

As stibine (SbH₃) is very similar to arsine (AsH₃), it is also detected by the Marsh test. This sensitive test detects arsine generated in the presence of arsenic. This procedure, developed around 1836 by James Marsh, is based upon treating a sample with arsenic-free zinc and dilute sulfuric acid: if the sample contains arsenic, gaseous arsine will form. The gas is swept into a glass tube and decomposed by means of heating around 250 – 300 °C. The presence of arsenic is indicated by formation of a deposit in the heated part of the equipment. The formation of a black mirror deposit in the cool part of the equipment indicates the presence of antimony.

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