Lead(II) chloride

Last updated
Lead(II) chloride
PbCl2precipiate.jpg
Cotunnite structure.png
Names
IUPAC names
Lead(II) chloride
Lead dichloride
Other names
Plumbous chloride
Cotunnite
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.028.950
EC Number
  • 231-845-5
PubChem CID
UNII
Properties
PbCl2
Molar mass 278.10 g/mol
Appearancewhite odorless solid
Density 5.85 g/cm3
Melting point 501 °C (934 °F; 774 K)
Boiling point 950 °C (1,740 °F; 1,220 K)
10.8 g/L (20 °C) [1]
1.7×10−5 (20 °C)
Solubility slightly soluble in dilute HCl, ammonia;
insoluble in alcohol

Soluble in hot water as well as in presence of alkali hydroxide

Contents

Soluble in concerntrated HCl (>6M)

73.8·10−6 cm3/mol
2.199 [2]
Structure
Orthorhombic, oP12
Pnma, No. 62
Thermochemistry
135.98 JK−1mol−1
-359.41 kJ/mol
Hazards [3]
Safety data sheet See: data page
GHS pictograms GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg GHS-pictogram-pollu.svg
GHS Signal word Danger
H302, H332, H351, H360, H372, H400, H410
P201, P261, P273, P304+340, P308+313, P312, P391
NFPA 704 (fire diamond)
Flammability code 0: Will not burn. E.g. waterHealth code 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no codeLead(II) chloride
0
3
0
Lethal dose or concentration (LD, LC):
1500 mg/kg (guinea pig, oral) [4]
Related compounds
Other anions
Lead(II) fluoride
Lead(II) bromide
Lead(II) iodide
Other cations
Lead(IV) chloride
Tin(II) chloride
Germanium(II) chloride
Related compounds
Thallium(I) chloride
Bismuth chloride
Supplementary data page
Refractive index (n),
Dielectric constantr), etc.
Thermodynamic
data
Phase behaviour
solidliquidgas
UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

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-based reagents. It also occurs naturally in the form of the mineral cotunnite.

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. [5] 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. [6] Such PbCl2 is emitted from internal combustion engines that use ethylene chloride-tetraethyllead additives for antiknock purposes.

PbCl2 is sparingly soluble in water, solubility product Ksp = 1.7×10−5 at 20 °C. It is one of only four commonly water-insoluble chlorides, the other three being silver chloride (AgCl) with Ksp = 1.8×10−10, copper(I) chloride (CuCl) with Ksp = 1.72×10−7 and mercury(I) chloride (Hg2Cl2) with Ksp = 1.3×10−18. [7] [8]

Occurrence

Crystal structure of cotunnite, PbCl2 Cotunnite-3D-balls.png
Crystal structure of cotunnite, PbCl2

PbCl2 occurs naturally in the form of the mineral cotunnite. It is colorless, white, yellow, or green with a density of 5.3–5.8 g/cm3. The hardness on the Mohs scale is 1.5–2. The crystal structure is orthorhombic dipyramidal and the point group is 2/m 2/m 2/m. Each Pb has a coordination number of 9. Cotunnite occurs near volcanoes: Vesuvius, Italy; Tarapacá, Chile; and Tolbachik, Russia. [9]

Synthesis

Lead(II) chloride precipitates from solution upon addition of chloride sources (HCl, NaCl, KCl) to aqueous solutions of lead(II) compounds such as Pb(NO3)2.

Pb(NO3)2(aq) + 2 NaCl (aq) → PbCl2(s) + 2 NaNO3 (aq)
Pb(CH3COO)2 (aq) + HCl (aq) → PbCl2(s) + 2 CH3COOH (aq)
basic PbCO3 + 2 HCl(aq) → PbCl2(s) + CO2(g) + H2O [10]
Pb(NO3)2(aq) + 2 HCl(aq) → PbCl2(s) + 2 HNO3(aq)

Treatment of lead dioxide with hydrochloric acid gives lead(II) chloride as well as chlorine gas:

PbO2(s) + 4 HCl → PbCl2(s) + Cl2 + 2 H2O

Treatment of lead oxide with hydrochloric acid gives lead(II) chloride as well as water

PbO(s) + 2 HCl → PbCl2(s) + H2O

PbCl2(s) also forms by the action of chlorine gas on lead metal:

Pb + Cl2 → PbCl2

Reactions

Addition of chloride ions to a suspension of PbCl2 gives rise to soluble complex ions. In these reactions the additional chloride (or other ligands) break up the chloride bridges that comprise the polymeric framework of solid PbCl2(s).

PbCl2(s) + Cl → [PbCl3](aq)
PbCl2(s) + 2 Cl → [PbCl4]2−(aq)

PbCl2 reacts with molten NaNO2 to give PbO:

PbCl2(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 [NH4]2[PbCl6]. The latter is reacted with cold concentrated sulfuric acid (H2SO4) forming PbCl4 as an oil. [11]

Lead(II) chloride is the main precursor for organometallic derivatives of lead, such as plumbocenes. [12] The usual alkylating agents are employed, including Grignard reagents 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 [13]

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

Uses

Toxicity

Like other lead containing compounds, exposure to PbCl2 may cause lead poisoning.

Related Research Articles

Acid–base reaction chemical reaction

An acid–base reaction is a chemical reaction that occurs between an acid and a base. It can be used to determine pH. Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their application in solving related problems; these are called the acid–base theories, for example, Brønsted–Lowry acid–base theory.

Salt (chemistry) Ionic compound consisting of cations and anions

In chemistry, a salt is a solid chemical compound consisting of an ionic assembly of cations and anions. Salts are composed of related numbers of cations and anions so that the product is electrically neutral. These component ions can be inorganic, such as chloride (Cl), or organic, such as acetate ; and can be monatomic, such as fluoride (F) or polyatomic, such as sulfate.

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 reaction with another constituent of the solvent, such as acid or alkali. Each type of equilibrium is characterized by a temperature-dependent equilibrium constant. Solubility equilibria are important in pharmaceutical, environmental and many other scenarios.

Ammonium cation, protonated ammonia

The ammonium cation is a positively charged polyatomic ion with the chemical formula NH+
4
. It is formed by the protonation of ammonia (NH3). Ammonium is also a general name for positively charged or protonated substituted amines and quaternary ammonium cations (NR+
4
), where one or more hydrogen atoms are replaced by organic groups (indicated by R).

In chemistry, an amphoteric compound is a molecule or ion that can react both as an acid and as a base. Many metals (such as copper, zinc, tin, lead, aluminium, and beryllium) form amphoteric oxides or hydroxides. Amphoterism depends on the oxidation states of the oxide. Al2O3 is an example of an amphoteric oxide.

Iron(III) chloride chemical compound

Iron(III) chloride is the inorganic compound with the formula. Also called ferric chloride, it is a common compound of iron in the +3 oxidation state. The anhydrous compound is a crystalline solid with a melting point of 307.6 °C. The color depends on the viewing angle: by reflected light the crystals appear dark green, but by transmitted light they appear purple-red.

In chemistry, a reactivity series (or activity series) is an empirical, calculated, and structurally analytical progression of a series of metals, arranged by their "reactivity" from highest to lowest. It is used to summarize information about the reactions of metals with acids and water, double displacement reactions and the extraction of metals from their ores.

Zinc chloride chemical compound

Zinc chloride is the name of chemical compounds with the formula ZnCl2 and its hydrates. Zinc chlorides, of which nine crystalline forms are known, are colorless or white, and are highly soluble in water. ZnCl2 itself is hygroscopic and even deliquescent. Samples should therefore be protected from sources of moisture, including the water vapor present in ambient air. Zinc chloride finds wide application in textile processing, metallurgical fluxes, and chemical synthesis. No mineral with this chemical composition is known aside from the very rare mineral simonkolleite, Zn5(OH)8Cl2·H2O.

Barium chloride chemical compound

Barium chloride is the inorganic compound with the formula BaCl2. It is one of the most common water-soluble salts of barium. Like most other barium salts, it is white, toxic, and imparts a yellow-green coloration to a flame. It is also hygroscopic, converting first to the dihydrate BaCl2(H2O)2. It has limited use in the laboratory and industry.

Silver chloride chemical compound

Silver chloride is a chemical compound with the chemical formula AgCl. This white crystalline solid is well known for its low solubility in water (this behavior being reminiscent of the chlorides of Tl+ and Pb2+). Upon illumination or heating, silver chloride converts to silver (and chlorine), which is signaled by grey to black or purplish coloration to some samples. AgCl occurs naturally as a mineral chlorargyrite.

Classical qualitative inorganic analysis is a method of analytical chemistry which seeks to find the elemental composition of inorganic compounds. It is mainly focused on detecting ions in an aqueous solution, therefore materials in other forms may need to be brought to this state before using standard methods. The solution is then treated with various reagents to test for reactions characteristic of certain ions, which may cause color change, precipitation and other visible changes.

Gold(III) chloride chemical compound

Gold(III) chloride, traditionally called auric chloride, is a chemical compound of gold and chlorine. With the molecular formula Au2Cl6, the name gold trichloride is a simplification, referring to the empirical formula, AuCl3. The Roman numerals in the name indicate that the gold has an oxidation state of +3, which is common for gold compounds. There is also another related chloride of gold, gold(I) chloride (AuCl). Chloroauric acid, HAuCl4, the product formed when gold dissolves in aqua regia, is sometimes referred to as "gold chloride" or "acid gold trichloride". Gold(III) chloride is very hygroscopic and highly soluble in water as well as ethanol. It decomposes above 160 °C or in light.

Tin(II) chloride chemical compound

Tin(II) chloride, also known as stannous chloride, is a white crystalline solid with the formula SnCl2. It forms a stable dihydrate, but aqueous solutions tend to undergo hydrolysis, particularly if hot. SnCl2 is widely used as a reducing agent (in acid solution), and in electrolytic baths for tin-plating. Tin(II) chloride should not be confused with the other chloride of tin; tin(IV) chloride or stannic chloride (SnCl4).

A strong electrolyte is a solution/solute that completely, or almost completely, ionizes or dissociates in a solution. These ions are good conductors of electric current in the solution.

Organolead compound any organometallic compound having a carbon–lead bond

Organolead compounds are chemical compounds containing a chemical bond between carbon and lead. Organolead chemistry is the corresponding science. The first organolead compound was hexaethyldilead (Pb2(C2H5)6), first synthesized in 1858. Sharing the same group with carbon, lead is tetravalent.

Bismuth chloride chemical compound

Bismuth chloride (or butter of bismuth) 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.

Germanium dichloride is a chemical compound of germanium and chlorine with the formula GeCl2. It is a solid and contains germanium in the +2 oxidation state.

Metal halides class of chemical compounds

Metal halides are compounds between metals and halogens. Some, such as sodium chloride are ionic, while others are covalently bonded. Covalently bonded metal halides may be discrete molecules, such as uranium hexafluoride, or they may form polymeric structures, such as palladium chloride.

Compounds of lead exist in two main oxidation states: +2 and +4. The former is more common. Inorganic lead(IV) compounds are typically strong oxidants or exist only in highly acidic solutions.

References

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  8. Brown, Lemay, Burnsten. Chemistry The Central Science. "Solubility-Product Constants for Compounds at 25 °C". (ed 6, 1994). p. 1017
  9. Cotunnite
  10. 1 2 Dictionary of Inorganic and Organometallic Compounds. Lead(II) Chloride.
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  15. Stained Glass Terms and Definitions. aurene glass
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