Bismuthine
Encyclopedia
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(III) species having the general formula , where R is an organic substituent. For example, Bi(CH3)3 is trimethylbismuthine.
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 with respect to its elements. The gas decomposes according to the following equation:
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.
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
with the formula BiH3. As the heaviest analogue of ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
, BiH3 is unstable, decomposing to bismuth
Bismuth
Bismuth is a chemical element with symbol Bi and atomic number 83. Bismuth, a trivalent poor metal, chemically resembles arsenic and antimony. Elemental bismuth may occur naturally uncombined, although its sulfide and oxide form important commercial ores. The free element is 86% as dense as lead...
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(III) species having the general formula , where R is an organic substituent. For example, Bi(CH3)3 is trimethylbismuthine.
Preparation and properties
BiH3 is prepared by the redistribution of methylbismuthine (BiH2Me):- 3 BiH2Me → 2 BiH3 + BiMe3
The required BiH2Me, which is also thermally unstable, is generated by reduction of methylbismuth dichloride, BiCl2Me with LiAlH4
Lithium aluminium hydride
Lithium aluminium hydride, commonly abbreviated to LAH or known as LithAl, is an inorganic compound with the chemical formula LiAlH4. It was discovered by Finholt, Bond and Schlesinger in 1947. This compound is used as a reducing agent in organic synthesis, especially for the reduction of esters,...
.
As suggested by the behavior of SbH3
Stibine
Stibine is the chemical compound with the formula SbH3. 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 1.707 Å...
, 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
Marsh test
The Marsh test is a highly sensitive method in the detection of arsenic, especially useful in the field of forensic toxicology when arsenic was used as a poison...
") 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
Hypochlorite
The hypochlorite ion, also known as chlorate anion is ClO−. A hypochlorite compound is a chemical compound containing this group, with chlorine in oxidation state +1.Hypochlorites are the salts of hypochlorous acid...
, Sb dissolves in ammonium polysulfide
Polysulfide
Polysulfides are a class of chemical compounds containing chains of sulfur atoms. There are two main classes of polysulfides: anions and organic polysulfides. Anions have the general formula Sn2−. These anions are the conjugate bases of the hydrogen polysulfides H2nSn...
, and Bi resists both reagents.