Bismuth forms mainly
trivalent and a few
pentavalent compounds. Many of its chemical properties are similar to those of
arsenic and
antimony, although much less toxic.[1]
Oxides and sulfides
At elevated temperatures, vaporized bismuth metal and oxygen combine into the yellow trioxide,
Bi 2O 3.[2][3] At temperatures above 710 °C, this (molten) oxide corrodes all known oxides and even platinum.[4] It forms two series of
oxyanions in basic conditions: linear, chain-polymeric BiO− 2; and cubic BiO3− 3. In Li 3BiO 3, the anion forms the octamer Bi 8O24− 24; in Na 3BiO 3, the tetramer.[5]
The dark red bismuth(V) oxide, Bi 2O 5, is unstable, liberating
O 2 gas upon heating.[6] The compound
NaBiO3 is a strong oxidant.[7]
Bismuth sulfide,
Bi 2S 3, occurs naturally in bismuth ores,[8] but can be synthesized from molten bismuth and sulfur.[9]
The oxidation state +5 is less frequently encountered. One such compound is the powerful oxidant and fluorinator,
BiF 5. It is also a strong fluoride acceptor, forming the XeF+ 3 cation from
xenon tetrafluoride:[10]
BiF 5 + XeF 4 → XeF+ 3BiF− 6
The
low-oxidation-state bismuth halides adopt unusual cluster structures. What was originally thought bismuth(I) chloride, BiCl, is in fact a lattice of Bi5+ 9 cations and BiCl2− 5 and Bi 2Cl2− 8 anions.[5][11] The Bi5+ 9 cation has a distorted tricapped
trigonal prismatic molecular geometry and is also found in Bi 10Hf 3Cl 18, which is prepared by reducing a mixture of
hafnium(IV) chloride and
bismuth chloride with elemental bismuth, having the structure [Bi+ ] [Bi5+ 9] [HfCl2− 6 3.[5]: 50 Other
polyatomic bismuth cations are also known, such as Bi2+ 8, found in Bi 8(AlCl 4) 2.[11]
There is a true monoiodide, BiI, which contains chains of Bi 4I 4 units. BiI decomposes upon heating to the triiodide,
BiI 3, and elemental bismuth.[5]
Bismuth forms at least two "monobromides": one isostructural to "BiCl"[citation needed] and one isostructural to Bi 4I 4.[5]
Aqueous species and the bismuthyl cation
In
aqueous solution, the Bi3+ ion is solvated to form the aqua ion Bi(H 2O)3+ 8 in strongly acidic conditions.[12] At pH > 0 polynuclear species exist, the most important of which is believed to be the octahedral complex [Bi 6O 4(OH) 46+ .[13]
Bismuth oxychloride (BiOCl) and
bismuth oxynitrate (BiONO3) stoichiometrically appear simple anionic salts of the
bismuthyl(III) cation (BiO+), which commonly occurs in aqueous bismuth compounds. However, in the case of BiOCl, the salt crystal forms alternating plates of Bi, O, and Cl atoms. Each oxygen coordinates with four bismuth atoms in the adjacent plane.[14]
Bismuthine and bismuthides
Unlike the lighter
pnictogens nitrogen, phosphorus, and arsenic, but similar to
antimony, bismuth does not form a stable
hydride. Bismuth hydride,
bismuthine (BiH 3), is an
endothermic compound that spontaneously decomposes at room temperature. It is stable only below −60 °C.[5]Bismuthides are
intermetallic compounds between bismuth and other metals.[15]
In 2014 researchers discovered that sodium bismuthide admits bulk 3D
Dirac fermions. As a
topologicalDirac semi-metal, it is a three-dimensional counterpart to
graphene with similar
electron mobility and velocity. While sodium bismuthide (Na 3Bi) is too unstable to be used in devices without packaging, it may offer distinct efficiency and fabrication advantages over planar graphene in
semiconductor and
spintronics applications.[16][17]
Bismuth oxychloride is a
pigment and cosmetic.[14]
Bismuth vanadate is an opaque yellow pigment used by some artists' oil,
acrylic, and watercolor paint companies, primarily as a replacement for the more toxic
cadmium sulfide yellows in the greenish-yellow (lemon) to orange-toned yellow range. It performs practically identically to the cadmium pigments in UV resistance, opacity, tinting strength, and inertness when mixed with other pigments. The most commonly-used variety by artists' paint makers is lemon in color.
The vanadate also replaces older zinc, lead, and strontium chromate pigments for much the same reason. With a green pigment and barium sulfate (for increased transparency), it can also replace the greenish-tinted
barium chromate. Unlike
lead chromates, it does not blacken from atmospheric
hydrogen sulfide and possesses a particularly brighter color. The difference is especially apparent with the lemon, which has a more
concentratedlead sulfate mixture.
Vanadate paints are also used, on a limited basis due to its cost, on vehicles.[18][19]
Bismuth strontium calcium copper oxide (BSCCO) is a superconducting compound family discovered in 1988. Its members exhibit the highest superconducting transition temperatures at standard pressure.[22]
δ-
Bismuth oxide is a solid electrolyte for oxygen. This form is stable only at high temperature, but can be electrodeposited well below this temperature in highly alkaline solution.
^Levason, W.; Reid, G. (2003). "Coordination Chemistry of the s, p, and f Metals". Comprehensive Coordination Chemistry II. Amsterdam: Elsevier Pergamon.
doi:
10.1016/B0-08-043748-6/02023-5.
ISBN0-08-043748-6.
^
abcdefgGodfrey, S. M.; McAuliffe, C. A.; Mackie, A. G.; Pritchard, R. G. (1998). Nicholas C. Norman (ed.). Chemistry of arsenic, antimony, and bismuth. Springer. pp. 67–84.
ISBN978-0-7514-0389-3.
^Näslund, Jan; Persson, Ingmar; Sandström, Magnus (2000). "Solvation of the Bismuth(III) Ion by Water, Dimethyl Sulfoxide, N,N'-Dimethylpropyleneurea, and N,N-Dimethylthioformamide. An EXAFS, Large-Angle X-ray Scattering, and Crystallographic Structural Study". Inorganic Chemistry. 39 (18): 4012–4021.
doi:
10.1021/ic000022m.
PMID11198855.
^Tücks, Andreas; Beck, Horst P. (2007). "The photochromic effect of bismuth vanadate pigments: Investigations on the photochromic mechanism". Dyes and Pigments. 72 (2): 163.
doi:
10.1016/j.dyepig.2005.08.027.