Lead(II) bromide
Lead(II) bromide
Names
IUPAC name
Lead(II) bromide
Other names
Lead dibromide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.030.065
EC Number
  • 233-084-4
UNII
  • InChI=1S/2BrH.Pb/h2*1H;/q;;+2/p-2
    Key: ZASWJUOMEGBQCQ-UHFFFAOYSA-L
  • Br[Pb]Br
Properties
PbBr2
Molar mass 367.01 g/mol
Appearance white powder
Density 6.66 g/cm3 [1]
Melting point 370.6 °C (699.1 °F; 643.8 K)
Boiling point 916 °C (1,681 °F; 1,189 K) (vaporizes)
0.455 g/100 mL (0 °C)
0.973 g/100 mL (20 °C)[2]
4.41 g/100 mL (100 °C)
1.86 x 10−5 (20 °C)
Solubility insoluble in alcohol;
soluble in ammonia, alkali, KBr, NaBr
−90.6·10−6 cm3/mol
Structure[3]
PbCl2 type (orthorhombic)
Pnma (No. 62)
a = 805.90 pm, b = 954.0 pm, c = 473.19 pm
4
Hazards
GHS labelling:
GHS07: Exclamation markGHS08: Health hazardGHS09: Environmental hazard
Danger
H302, H332, H360, H373, H410
P201, P202, P260, P261, P264, P270, P271, P273, P281, P301+P312, P304+P312, P304+P340, P308+P313, P312, P314, P330, P391, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamond
3
0
0
Related compounds
Other anions
 Lead(II) fluoride,
Lead(II) chloride,
Lead(II) iodide
Other cations
 Thallium(I) bromide,
Tin(II) bromide
Bismuth bromide
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) bromide is the inorganic compound with the formula PbBr2. It is a white powder. It is produced in the burning of typical leaded gasolines.[4]

Preparation and properties

It is typically prepared from treating solutions of lead salts (e.g., (lead(II) nitrate) with bromide salts. This process exploits its low solubility in water - only 0.455 g dissolves in 100 g of water at 0 °C. It is about ten times more soluble in boiling water.[5]

PbBr2 has the same crystal structure as lead chloride (cotunnite) – they are isomorphous. In this structure, Pb2+ is surrounded by nine Br− ions in a distorted tricapped trigonal prismatic geometry. Seven of the Pb-Br distances are shorter, in the range 2.9-3.3 Å, while two of them are longer at 3.9 Å. The coordination is therefore sometimes described as (7+2).[6][3]

Lead bromide was prevalent in the environment as the result of the use of leaded gasoline. Tetraethyl lead was once widely used to improve the combustion properties of gasoline. To prevent the resulting lead oxides from fouling the engine, gasoline was treated with 1,2-Dibromoethane, which converted lead oxides into the more volatile lead bromide, which was then exhausted from the engine into the environment.[4]

Safety

Like other compounds containing lead, lead(II) bromide is categorized as probably carcinogenic to humans (Category 2A), by the International Agency for Research on Cancer (IARC). Its release into the environment as a product of leaded gasoline was highly controversial.

References

  1. ↑ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3.
  2. ↑ NIST-data review 1980
  3. 1 2 Lumbreras, M.; Protas, J.; Jebbari, S.; Dirksen, G. J.; Schoonman, J. (1986). "Structure and ionic conductivity of mixed lead halides PbCl2xBr2(1−x). II". Solid State Ion. 20 (4): 295–304. doi:10.1016/0167-2738(86)90049-4.
  4. 1 2 Michael J. Dagani, Henry J. Barda, Theodore J. Benya, David C. Sanders "Bromine Compounds" in Ullmann's Encyclopedia of Industrial Chemistry" Wiley-VCH, Weinheim, 2000.doi:10.1002/14356007.a04_405
  5. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  6. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 382. ISBN 978-0-08-037941-8.
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