Lead(II) chloride (PbCl₂) is an inorganic compound which is a white solid under ambient conditions. It is poorly soluble in water. Lead(II) chloride is one of the most important

lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...

-based

reagent In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...

s. It also occurs naturally in the form of the mineral

cotunnite Cotunnite is the natural mineral form of lead(II) chloride (PbCl2). Unlike the pure compound, which is white, cotunnite can be white, yellow, or green. The density of mineral samples spans range 5.3–5.8 g/cm3. The hardness on the Mohs scale is 1 ...

Structure and properties

In solid PbCl₂, each lead ion is coordinated by nine chloride ions in a tricapped triangular prism formation — six lie at the vertices of a triangular prism and three lie beyond the centers of each rectangular prism face. The 9 chloride ions are not equidistant from the central lead atom, 7 lie at 280–309 pm and 2 at 370 pm. PbCl₂ forms white orthorhombic needles. In the gas phase, PbCl₂ molecules have a bent structure with the Cl–Pb–Cl angle being 98° and each Pb–-Cl bond distance being 2.44 Å. Such PbCl₂ is emitted from internal combustion engines that use ethylene chloride-

tetraethyllead Tetraethyllead (commonly styled tetraethyl lead), abbreviated TEL, is an organolead compound with the formula lead, Pb(ethyl group, C2H5)4. It was widely used as a fuel additive for much of the 20th century, first being mixed with gasoline begi ...

additives for antiknock purposes. PbCl₂ is sparingly soluble in water,

solubility product Solubility equilibrium is a type of dynamic equilibrium that exists when a chemical compound in the solid state is in chemical equilibrium with a solution of that compound. The solid may dissolve unchanged, with dissociation, or with chemical reac ...

''K''_sp = at 20 °C. It is one of only 5 commonly water-insoluble chlorides, the other 4 being

thallium(I) chloride Thallium(I) chloride, also known as thallous chloride, is a chemical compound with the formula TlCl. This colourless salt is an intermediate in the isolation of thallium from its ores. Typically, an acidic solution of thallium(I) sulfate is treate ...

silver chloride Silver chloride is an inorganic chemical compound with the chemical formula Ag Cl. This white crystalline solid is well known for its low solubility in water and its sensitivity to light. Upon illumination or heating, silver chloride converts ...

(AgCl) with ''K''_sp = ,

copper(I) chloride Copper(I) chloride, commonly called cuprous chloride, is the lower chloride of copper, with the formula CuCl. The substance is a white solid sparingly soluble in water, but very soluble in concentrated hydrochloric acid. Impure samples appear gr ...

(CuCl) with ''K''_sp = and

mercury(I) chloride Mercury(I) chloride is the chemical compound with the formula Hg2Cl2. Also known as the mineral calomel (a rare mineral) or mercurous chloride, this dense white or yellowish-white, odorless solid is the principal example of a mercury(I) compoun ...

(Hg₂Cl₂) with ''K''_sp = .

Synthesis

Solid lead(II) chloride

precipitate In an aqueous solution, precipitation is the "sedimentation of a solid material (a precipitate) from a liquid solution". The solid formed is called the precipitate. In case of an inorganic chemical reaction leading to precipitation, the chemic ...

s upon addition of aqueous

chloride The term chloride refers to a compound or molecule that contains either a chlorine anion (), which is a negatively charged chlorine atom, or a non-charged chlorine atom covalently bonded to the rest of the molecule by a single bond (). The pr ...

sources (HCl, NaCl, KCl) to aqueous solutions of

(II) compounds, such as

lead(II) nitrate Lead(II) nitrate is an inorganic compound with the chemical formula Pb( NO3)2. It commonly occurs as a colourless crystal or white powder and, unlike most other lead(II) salts, is soluble in water. Known since the Middle Ages by the name plumbum ...

and

lead(II) acetate Lead(II) acetate is a white crystalline chemical compound with a slightly sweet taste. Its chemical formula is usually expressed as or , where Ac represents the acetyl group. Like many other lead compounds, it causes lead poisoning. Lead aceta ...

: : It also forms by treatment of basic lead(II) compounds such as

Lead(II) oxide Lead(II) oxide, also called lead monoxide, is the inorganic compound with the molecular formula Pb O. It occurs in two polymorphs: litharge having a tetragonal crystal structure, and massicot having an orthorhombic crystal structure. Modern ...

and

lead(II) carbonate Lead(II) carbonate is the chemical compound with the chemical formula . It is a white, toxic solid. It occurs naturally as the mineral cerussite. Structure Like all metal carbonates, lead(II) carbonate adopts a dense, highly crosslinked structure ...

Lead dioxide Lead(IV) oxide, commonly known as lead dioxide, is an inorganic compound with the chemical formula . It is an oxide where lead is in an oxidation state of +4. It is a dark-brown solid which is insoluble in water. It exists in two crystalline forms ...

is reduced by chloride as follows: : It also formed by the oxidation of lead metal by

copper(II) chloride Copper(II) chloride, also known as cupric chloride, is an inorganic compound with the chemical formula . The monoclinic crystal system, monoclinic yellowish-brown anhydrous form slowly absorbs moisture to form the orthorhombic blue-green hydrate, ...

: : Or most straightforwardly by the action of

chlorine Chlorine is a chemical element; it has Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between ...

gas on lead metal: :

Reactions

Addition of chloride ions to a suspension of PbCl₂ gives rise to soluble

complex Complex commonly refers to: * Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe ** Complex system, a system composed of many components which may interact with each ...

ions. In these reactions the additional chloride (or other

ligand In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's el ...

s) break up the chloride bridges that comprise the polymeric framework of solid PbCl_2(s). :PbCl_2(s) + Cl⁻ → bCl₃sup>−_(aq) :PbCl_2(s) + 2 Cl⁻ → bCl₄sup>2−_(aq) PbCl₂ reacts with molten NaNO₂ to give PbO: :PbCl_2(l) + 3 NaNO₂ → PbO + NaNO₃ + 2 NO + 2 NaCl PbCl₂ is used in synthesis of lead(IV) chloride (PbCl₄): Cl₂ is bubbled through a saturated solution of PbCl₂ in aqueous NH₄Cl forming H₄sub>2 bCl₆ The latter is reacted with cold concentrated

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...

(H₂SO₄) forming PbCl₄ as an oil. Lead(II) chloride is the main

precursor Precursor or Precursors may refer to: *Precursor (religion), a forerunner, predecessor ** The Precursor, John the Baptist Science and technology * Precursor (bird), hypothesized genus of fossil birds that was composed of fossilized parts of unre ...

for

organometallic Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and so ...

derivatives of lead, such as

plumbocene Plumbocene is an organometallic compound of lead with the chemical formula . It is a member of the class of metallocenes. It is soluble in benzene, acetone, ether, and petroleum ether, and insoluble in water. Plumbocene is stable in cold water. G ...

s. The usual alkylating agents are employed, including

Grignard reagent Grignard reagents or Grignard compounds are chemical compounds with the general formula , where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride and phenylmagnesium bromi ...

s and organolithium compounds: :2 PbCl₂ + 4 RLi → R₄Pb + 4 LiCl + Pb :2 PbCl₂ + 4 RMgBr → R₄Pb + Pb + 4 MgBrCl :3 PbCl₂ + 6 RMgBr → R₃Pb-PbR₃ + Pb + 6 MgBrCl These reactions produce derivatives that are more similar to organosilicon compounds, ''i.e.'' that Pb(II) tends to disproportionate upon alkylation. PbCl₂ can be used to produce PbO₂ by treating it with

sodium hypochlorite Sodium hypochlorite is an alkaline inorganic chemical compound with the formula (also written as NaClO). It is commonly known in a dilute aqueous solution as bleach or chlorine bleach. It is the sodium salt of hypochlorous acid, consisting of ...

(NaClO), forming a reddish-brown precipitate of PbO₂.

Uses

*Molten PbCl₂ is used in the synthesis of lead titanate and

barium Barium is a chemical element; it has symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element. Th ...

lead titanate ceramics by cation replacement reactions: *:''x'' PbCl_2(l) + BaTiO_3(s) → Ba_1−''x''Pb_''x''TiO₃ + ''x'' BaCl₂ *PbCl₂ is used in production of infrared transmitting glass,Dictionary of Inorganic and Organometallic Compounds. ''Lead(II) Chloride.

/ref> and ornamental glass called aurene glass. Aurene glass has an iridescent surface formed by spraying with PbCl₂ and reheating under controlled conditions.

Stannous chloride Tin(II) chloride, also known as stannous chloride, is a white crystalline solid with the formula . It forms a stable dihydrate, but aqueous solutions tend to undergo hydrolysis, particularly if hot. SnCl2 is widely used as a reducing agent (in aci ...

(SnCl₂) is used for the same purpose. *Pb is used in HCl service even though the PbCl₂ formed is slightly soluble in HCl. Addition of 6–25% of

antimony Antimony is a chemical element; it has chemical symbol, symbol Sb () and atomic number 51. A lustrous grey metal or metalloid, it is found in nature mainly as the sulfide mineral stibnite (). Antimony compounds have been known since ancient t ...

(Sb) increases corrosion resistance. *A basic chloride of lead, PbCl₂·Pb(OH)₂, is known as Pattinson's

white lead White lead is the basic lead carbonate 2PbCO3·Pb(OH)2. It is a complex Salt (chemistry), salt, containing both carbonate and hydroxide ions. White lead occurs naturally as a mineral, in which context it is known as hydrocerussite, a hydrate of ...

and is used as pigment in white paint.

Lead paint Lead paint or lead-based paint is paint containing lead. As pigment, lead(II) chromate (, "chrome yellow"), lead(II,IV) oxide, (, "red lead"), and lead(II) carbonate (, "white lead") are the most common forms.. Lead is added to paint to acceler ...

is now banned as a health hazard in many countries by the

White Lead (Painting) Convention, 1921 White Lead (Painting) Convention, 1921 is an International Labour Organization Convention established in 1921 to advance the prohibition of using white lead in paint. As of 2017 many leading global nations, including the United States, the Uni ...

. *PbCl₂ is an intermediate in refining

bismuth Bismuth is a chemical element; it has 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 nat ...

(Bi) ore. The ore containing Bi, Pb, and Zn is first treated with molten

caustic soda Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base and alkali t ...

to remove traces of

arsenic Arsenic is a chemical element; it has Symbol (chemistry), symbol As and atomic number 33. It is a metalloid and one of the pnictogens, and therefore shares many properties with its group 15 neighbors phosphorus and antimony. Arsenic is not ...

and

tellurium Tellurium is a chemical element; it has symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally fou ...

. This is followed by the

Parkes process The Parkes process is a pyrometallurgical industrial process for removing silver from lead during the production of bullion. It is an example of liquid–liquid extraction. The process takes advantage of two liquid-state properties of zinc. The fi ...

to remove any silver and gold present. There are now Bi, Pb, and Zn in the ore. At 500 °C, it receives treatment from Cl2 gas. First, ZnCl2 forms and is excreted. Pure Bi is left behind after PbCl2 forms and is eliminated. Lastly, BiCl3 would form.Kirk-Othmer. ''Encyclopedia of Chemical Technology''. (ed 4). p. 241

Toxicity

Like other soluble lead compounds, exposure to PbCl₂ may cause

lead poisoning Lead poisoning, also known as plumbism and saturnism, is a type of metal poisoning caused by lead in the body. Symptoms may include abdominal pain, constipation, headaches, irritability, memory problems, infertility, numbness and paresthesia, t ...

References

External links

IARC Monograph: "Lead and Lead Compounds"

* ttps://www.atsdr.cdc.gov/csem/csem.html Case Studies in Environmental Medicine – Lead Toxicity
ToxFAQs: Lead
{{Chlorides Lead(II) compounds Chlorides Metal halides IARC Group 2A carcinogens