Lead(II) bromide

Lead(II) bromide
Names
	IUPAC name Lead(II) bromide
	Other names Lead dibromide
Identifiers
CAS Number	10031-22-8 ;
3D model (JSmol)	Interactive image;
ChemSpider	23216;
ECHA InfoCard	100.030.065
EC Number	233-084-4;
PubChem CID	24831;
UNII	1O767M99U7 ;
CompTox Dashboard (EPA)	DTXSID701014306 ;
	InChI InChI=1S/2BrH.Pb/h2*1H;/q;;+2/p-2 Key: ZASWJUOMEGBQCQ-UHFFFAOYSA-L;
	SMILES Br[Pb]Br;
Properties
Chemical formula	PbBr2
Molar mass	367.01 g/mol
Appearance	white powder
Density	6.66 g/cm3
Melting point	370.6 °C (699.1 °F; 643.8 K)
Boiling point	916 °C (1,681 °F; 1,189 K) (vaporizes)
Solubility in water	0.455 g/100 mL (0 °C) ; 0.973 g/100 mL (20 °C) ; 4.41 g/100 mL (100 °C)
Solubility product (Ksp)	1.86 x 10−5 (20 °C)
Solubility	insoluble in alcohol; ; soluble in ammonia, alkali, KBr, NaBr
Magnetic susceptibility (χ)	−90.6·10−6 cm3/mol
Structure
Crystal structure	PbCl2 type (orthorhombic)
Space group	Pnma (No. 62)
Lattice constant	a = 805.90 pm, b = 954.0 pm, c = 473.19 pm
Formula units (Z)	4
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H332, H360, H373, H410
Precautionary statements	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)	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). verify (what is ?) 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

^ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, Florida: CRC Press. ISBN 0-8493-0487-3.
^ NIST-data review 1980
^ ^a ^b Lumbreras, M.; Protas, J.; Jebbari, S.; Dirksen, G. J.; Schoonman, J. (1986). "Structure and ionic conductivity of mixed lead halides PbCl_2xBr_2(1−x). II". Solid State Ion. 20 (4): 295–304. doi:10.1016/0167-2738(86)90049-4.
^ ^a ^b 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
^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 382. ISBN 978-0-08-037941-8.

[1] Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, Florida: CRC Press. ISBN 0-8493-0487-3.

[2] NIST-data review 1980

[Lumbreras1986-3] Lumbreras, M.; Protas, J.; Jebbari, S.; Dirksen, G. J.; Schoonman, J. (1986). "Structure and ionic conductivity of mixed lead halides PbCl_2xBr_2(1−x). II". Solid State Ion. 20 (4): 295–304. doi:10.1016/0167-2738(86)90049-4.

[Ullmann-4] 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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