Bismuth chloride
Encyclopedia
Bismuth chloride is an inorganic compound
with the chemical formula BiCl3. It is a common source of the Bi3+ ion. In the gas phase and in the crystal, the species adopts a pyramidal structure, in accord with VSEPR theory
.
over bismuth
.
Alternatively, the chloride salt may be prepared by adding hydrochloric acid
to bismuth oxide and evaporating the solution.
Bi2O3 + 6 HCl → 2 BiCl3 + 3 H2O
Also, the compound can be prepared by dissolving bismuth in concentrated nitric acid
and then adding solid sodium chloride
into this solution.
readily to bismuth oxychloride
, BiOCl:
This reaction can be suppressed by adding an acid, such as hydrochloric acid
.
Bismuth chloride is an oxidizing agent, being readily reduced to metallic bismuth by reducing agents.
, forming a variety of chloro complexes such as [BiCl6]3− that strongly violates the octet rule
. Furthermore the octahedral structure of this coordination complex does not follow the predictions of VSEPR theory, since the lone pair
on bismuth is unexpectedly stereochemically inactive. The dianionic complex [BiCl5]2− does however adopt the expected square pyramidal structure.
. In particular, it catalyzes the Michael reaction
and the Mukaiyama-aldol reaction. The addition of other metal iodide
s increases its catalytic activity.
as does the molten material. It is used to prepare several other bismuth salts, and is a constituent in pigment
s and cosmetics
.
Inorganic compound
Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...
with the chemical formula BiCl3. It is a common source of the Bi3+ ion. In the gas phase and in the crystal, the species adopts a pyramidal structure, in accord with VSEPR theory
VSEPR theory
Valence shell electron pair repulsion theory is a model in chemistry used to predict the shape of individual molecules based upon the extent of electron-pair electrostatic repulsion. It is also named Gillespie–Nyholm theory after its two main developers...
.
Preparation
Bismuth chloride is synthesized directly by passing chlorineChlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
over 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...
.
- 2 Bi + 3 Cl2 → 2 BiCl3
Alternatively, the chloride salt may be prepared by adding hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....
to bismuth oxide and evaporating the solution.
Bi2O3 + 6 HCl → 2 BiCl3 + 3 H2O
Also, the compound can be prepared by dissolving bismuth in concentrated nitric acid
Nitric acid
Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...
and then adding solid sodium chloride
Sodium chloride
Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...
into this solution.
- Bi + 6 HNO3 → Bi(NO3)3 + 3 H2O + 3 NO2
- Bi(NO3)3 + 3 NaCl → BiCl3 + 3 NaNO3
Chemistry
Bismuth chloride is hydrolyzedHydrolysis
Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization...
readily to bismuth oxychloride
Bismuth oxychloride
Bismuth oxychloride is a chemical compound of bismuth, oxygen, and chlorine, with the formula BiOCl. It exists in nature as the mineral bismoclite which is part of the matlockite mineral group.-Structure:...
, BiOCl:
- + + → BiOCl (s) + 2
This reaction can be suppressed by adding an acid, such as hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....
.
Bismuth chloride is an oxidizing agent, being readily reduced to metallic bismuth by reducing agents.
Chloro complexes
In contrast to the usual expectation by consistency with periodic trends, BiCl3 is a Lewis acidLewis acid
]The term Lewis acid refers to a definition of acid published by Gilbert N. Lewis in 1923, specifically: An acid substance is one which can employ a lone pair from another molecule in completing the stable group of one of its own atoms. Thus, H+ is a Lewis acid, since it can accept a lone pair,...
, forming a variety of chloro complexes such as [BiCl6]3− that strongly violates the octet rule
Octet rule
The octet rule is a chemical rule of thumb that states that atoms of low The octet rule is a chemical rule of thumb that states that atoms of low The octet rule is a chemical rule of thumb that states that atoms of low (The octet rule is a chemical rule of thumb that states that atoms of low (...
. Furthermore the octahedral structure of this coordination complex does not follow the predictions of VSEPR theory, since the lone pair
Lone pair
In chemistry, a lone pair is a valence electron pair without bonding or sharing with other atoms. They are found in the outermost electron shell of an atom, so lone pairs are a subset of a molecule's valence electrons...
on bismuth is unexpectedly stereochemically inactive. The dianionic complex [BiCl5]2− does however adopt the expected square pyramidal structure.
Organic catalysis
Bismuth chloride is used as a catalyst in organic synthesisOrganic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...
. In particular, it catalyzes the Michael reaction
Michael reaction
The Michael reaction or Michael addition is the nucleophilic addition of a carbanion or another nucleophile to an alpha, beta unsaturated carbonyl compound. It belongs to the larger class of conjugate additions. This is one of the most useful methods for the mild formation of C-C bonds...
and the Mukaiyama-aldol reaction. The addition of other metal iodide
Iodide
An iodide ion is the ion I−. Compounds with iodine in formal oxidation state −1 are called iodides. This page is for the iodide ion and its salts. For information on organoiodides, see organohalides. In everyday life, iodide is most commonly encountered as a component of iodized salt,...
s increases its catalytic activity.
Uses
Bismuth chloride is an excellent water soluble crystalline source of bismuth. Its aqueous solution conducts electricityElectricity
Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
as does the molten material. It is used to prepare several other bismuth salts, and is a constituent in pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...
s and cosmetics
Cosmetics
Cosmetics are substances used to enhance the appearance or odor of the human body. Cosmetics include skin-care creams, lotions, powders, perfumes, lipsticks, fingernail and toe nail polish, eye and facial makeup, towelettes, permanent waves, colored contact lenses, hair colors, hair sprays and...
.