Lead(II) iodide

Lead(II) iodide (or lead iodide) is a chemical compound with the formula PbI
2. At room temperature, it is a bright yellow odorless crystalline solid, that becomes orange and red when heated. It was formerly called plumbous iodide.

Lead(II) iodide
Names
Other names
Plumbous iodide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.030.220
EC Number
  • 233-256-9
PubChem CID
UNII
UN number 2291 3077
  • InChI=1S/2HI.Pb/h2*1H;/q;;+2/p-2 Y
    Key: RQQRAHKHDFPBMC-UHFFFAOYSA-L Y
  • InChI=1/2HI.Pb/h2*1H;/q;;+2/p-2
    Key: RQQRAHKHDFPBMC-NUQVWONBAP
SMILES
  • I[Pb]I
Properties
PbI
2
Molar mass 461.01 g/mol
Appearance bright yellow powder
Odor odorless
Density 6.16 g/cm3
Melting point 410 °C (770 °F; 683 K)
Boiling point 872 °C (1,602 °F; 1,145 K) decomp.
  • 0.44 g/L (0 °C)
  • 0.76 g/L (20 °C)
  • 4.1 g/L (100 °C)
Solubility product (Ksp)
4.41×10−9 (20 °C)
Solubility
  • insoluble in ethanol, cold HCl
  • soluble in alkalis, KI solution, methyl isopropyl ketone
Band gap 2.34 eV (direct)
Magnetic susceptibility (χ)
 −126.5·10−6 cm3/mol
Structure
Hexagonal hP6
Space group
 P63mc, No. 186
a = 0.4556 nm, b = 0.4556 nm, c = 1.3973 nm
α = 90°, β = 90°, γ = 120°°
2
octahedral
Thermochemistry
77.4 J/(mol·K)
Std molar
entropy (S⦵298)
 174.9 J/(mol·K)
Std enthalpy of
formation (ΔfH⦵298)
 -175.5 kJ/mol
-173.6 kJ/mol
Hazards
GHS labelling:
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)
3
0
0
Flash point Non-flammable
Related compounds
Other anions
Other cations
 Tin(II) iodide
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

The compound currently has a few specialized applications, such as the manufacture of solar cells, X-rays and gamma-ray detectors. Its preparation is an entertaining and popular demonstration in chemistry education, to teach topics such as precipitation reactions and stoichiometry. It is decomposed by light at temperatures above 125 °C (257 °F), and this effect has been used in a patented photographic process.

Lead iodide was formerly employed as a yellow pigment in some paints, with the name iodide yellow. However, that use has been largely discontinued due to its toxicity and poor stability.

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