Lead(II) chloride

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Lead(II) chloride
Lead(II) chloride Lead(II) chloride.jpg
Lead(II) chloride
Cotunnite structure.png
The crystal structure of PbCl2, in the unconventional crystallographic setting Pnam. This corresponds to the standard Pnma setting by switching the labels on the b and c axes.
Names
IUPAC names
Lead(II) chloride
Lead dichloride
Other names
Plumbous chloride
Cotunnite
Dichloroplumbylene
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.028.950 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 231-845-5
PubChem CID
UNII
  • InChI=1S/2ClH.Pb/h2*1H;/q;;+2/p-2 Yes check.svgY
    Key: HWSZZLVAJGOAAY-UHFFFAOYSA-L Yes check.svgY
  • Cl[Pb]Cl
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)
0.99 g/100 mL (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 concentrated HCl (>6M)

−73.8·10−6 cm3/mol
2.199 [2]
Structure [3]
Orthorhombic, oP12
Pnma (No. 62)
a = 762.040 pm, b = 453.420 pm, c = 904.520 pm
4
Thermochemistry
Std molar
entropy (S⦵298)
135.98 J K−1 mol−1
−359.41 kJ/mol
Hazards [4]
GHS labelling:
GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg GHS-pictogram-pollu.svg
Danger
H302, H332, H351, H360, H372, H410
P201, P261, P273, P304+P340, P308+P313, P312, P391
NFPA 704 (fire diamond)
NFPA 704.svgHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
3
0
0
Lethal dose or concentration (LD, LC):
140 mg/kg (guinea pig, oral) [5]
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
Lead(II) chloride (data page)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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. [6] 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. [7] 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 5 commonly water-insoluble chlorides, the other 4 being thallium(I) chloride, 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. [8] [9]

Synthesis

Solid lead(II) chloride precipitates upon addition of aqueous chloride sources (HCl, NaCl, KCl) to aqueous solutions of lead(II) compounds, such as lead(II) nitrate and lead(II) acetate:

Pb(NO3)2 + 2 HCl → PbCl2(s) + 2 HNO3

It also forms by treatment of basic lead(II) compounds such as Lead(II) oxide and lead(II) carbonate.

Lead dioxide is reduced by chloride as follows:

PbO2 + 4 HCl → PbCl2(s) + Cl2 + 2 H2O

It also formed by the oxidation of lead metal by copper(II) chloride:

Pb + CuCl2 → PbCl2 + Cu

Or most straightforwardly 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. [10]

Lead(II) chloride is the main precursor for organometallic derivatives of lead, such as plumbocenes. [11] 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 [12]

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 soluble lead compounds, exposure to PbCl2 may cause lead poisoning.

References

  1. ↑ NIST-data review 1980 Archived 2014-02-11 at the Wayback Machine
  2. ↑ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN   0-07-049439-8
  3. ↑ Sass, Ronald L.; Brackett, E. B.; Brackett, T. E. (1963). "THE CRYSTAL STRUCTURE OF LEAD CHLORIDE". The Journal of Physical Chemistry. 67 (12). American Chemical Society (ACS): 2863–2864. doi:10.1021/j100806a517. ISSN   0022-3654.
  4. ↑ "Classifications - CL Inventory". echa.europa.eu.
  5. ↑ "Lead compounds (as Pb)". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  6. ↑ Wells A. F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN   0-19-855370-6
  7. ↑ Hargittai, I; Tremmel, J; Vajda, E; Ishchenko, A; Ivanov, A; Ivashkevich, L; Spiridonov, V (1977). "Two independent gas electron diffraction investigations of the structure of plumbous chloride". Journal of Molecular Structure. 42: 147–151. Bibcode:1977JMoSt..42..147H. doi:10.1016/0022-2860(77)87038-5.
  8. ↑ CRC Handbook of Chemistry and Physics, 79th Edition, David R. Lide (Ed), p. 8-108
  9. ↑ Brown, Lemay, Burnsten. Chemistry The Central Science. "Solubility-Product Constants for Compounds at 25 °C". (ed 6, 1994). p. 1017
  10. ↑ Housecroft, C. E.; Sharpe, A. G. (2004). Inorganic Chemistry (2nd ed.). Prentice Hall. p. 365. ISBN   978-0-13-039913-7.
  11. ↑ Lowack, R (1994). "Decasubstituted decaphenylmetallocenes". J. Organomet. Chem. 476: 25–32. doi:10.1016/0022-328X(94)84136-5.
  12. ↑ Housecroft, C. E.; Sharpe, A. G. (2004). Inorganic Chemistry (2nd ed.). Prentice Hall. p. 524. ISBN   978-0-13-039913-7.
  13. ↑ Aboujalil, Almaz; Deloume, Jean-Pierre; Chassagneux, Fernand; Scharff, Jean-Pierre; Durand, Bernard (1998). "Molten salt synthesis of the lead titanate PbTiO3, investigation of the reactivity of various titanium and lead salts with molten alkali-metal nitrites". Journal of Materials Chemistry. 8 (7): 1601. doi:10.1039/a800003d.
  14. ↑ Dictionary of Inorganic and Organometallic Compounds. Lead(II) Chloride.
  15. ↑ Stained Glass Terms and Definitions. aurene glass
  16. ↑ Kirk-Othmer. Encyclopedia of Chemical Technology. (ed 4). p 913
  17. ↑ Perry & Phillips. Handbook of Inorganic Compounds. (1995). p 213
  18. ↑ Kirk-Othmer. Encyclopedia of Chemical Technology. (ed 4). p. 241
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