Bismuth subcarbonate (BiO)
2CO
3, sometimes written Bi
2O
2(CO
3) is a chemical compound of
bismuth
Bismuth is a chemical element with the symbol Bi and atomic number 83. It is a post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth occurs ...
containing both
oxide and
carbonate
A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate ...
anions. Bismuth is in the +3
oxidation state
In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...
. Bismuth subcarbonate occurs naturally as the mineral
bismutite
Bismutite or bismuthite is a bismuth carbonate mineral with formula Bi2(CO3)O2 (bismuth subcarbonate). Bismutite occurs as an oxidation product of other bismuth minerals such as bismuthinite and native bismuth in hydrothermal veins and pegmatites. ...
. Its structure consists of Bi–O layers and CO
3 layers and is related to
kettnerite, CaBi(CO
3)OF. It is light-sensitive.
Uses
It is highly
radiopaque
Radiodensity (or radiopacity) is opacity to the radio wave and X-ray portion of the electromagnetic spectrum: that is, the relative inability of those kinds of electromagnetic radiation to pass through a particular material. Radiolucency or hypod ...
and for example is used as a
filler in radiopaque
catheter
In medicine, a catheter (/ˈkæθətər/) is a thin tubing (material), tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgi ...
s which can be seen by x-ray. In modern medicine, bismuth subcarbonate has been made into
nanotube arrays that exhibit antibacterial properties. It is also used in fireworks to make
Dragon's egg
''Dragon's Egg'' is a 1980 hard science fiction novel by American writer Robert L. Forward. In the story, Dragon's Egg is a neutron star with a surface gravity 67 billion times that of Earth, and inhabited by cheela, intelligent creatures ...
s. It is a constituent of milk of bismuth which was a popular digestive tract
panacea
In Greek mythology, Panacea (Greek ''Πανάκεια'', Panakeia), a goddess of universal remedy, was the daughter of Asclepius and Epione. Panacea and her four sisters each performed a facet of Apollo's art:
* Panacea (the goddess of univers ...
in the 1930s.
Safety
Bismuth subcarbonate may be harmful if swallowed. It may irritate the respiratory and gastrointestinal tract.
Synthesis
Bismuth subcarbonate can be attained from the reaction between bismuth nanoparticles and the atmospheric carbon dioxide (CO
2) dissolved in water. Bismuth subcarbonate has the tendency to form nanoplates, but it can be also obtained as small round nanospheres (with controlled size) when it is grown in the presence of halloysite nanotubes. The high pH and high temperature of the aqueous solution helps to reduce the time of synthesis. It is readily formed on the surface of undoped
bismuth oxide
Bismuth(III) oxide is perhaps the most industrially important compound of bismuth. It is also a common starting point for bismuth chemistry. It is found naturally as the mineral bismite (monoclinic) and sphaerobismoite (tetragonal, much more rare ...
(β-Bi
2O
3 and γ-Bi
2O
3) nanoparticles even when they are not suspended in water.
Structure
Bismuth subcarbonate has a structure with a tetragonal unit cell. Layers of (BiO)
''n'' positively charged, and carbonate anion (CO
32-) are surrounding both sides of the (BiO) layer to compensate the charge. Usually, The (BiO)
'n'' layer grows perpendicular to the b axis.
[
]
References
External links
Source of the common name; milk of bismuth
{{Carbonates
Bismuth compounds
Carbonates