Lead(II) iodide

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   Lead(II) iodide   
Names: lead(II) iodide
lead(II) diiodide

Formula: PbI2
Molar mass: 461.000 g/mol
Density: 6.16 g/cm3
Crystal system: hexagonal (α)
a=4.557 Å, b=4.557 Å, c=6.979 Åα=90°, β=90°, γ=120°
hexagonal (β)
a=4.557 Å, b=4.557 Å, c=34.895 Åα=90°, β=90°, γ=120°
hexagonal (γ)
a=4.557 Å, b=4.557 Å, c=48.853 Åα=90°, β=90°, γ=120°

Color: golden
Melting point: 412 °C685.15 K <br />773.6 °F <br />1,233.27 °R <br />
Boiling point: 872 °C1,145.15 K <br />1,601.6 °F <br />2,061.27 °R <br />
Magnetic properties: diamagnetic
χ=-1.27 · 10-4cm³/mol
Hardness: very fragile
Toxicity: poisonous


Inorganic compound, salt of bivalent metal lead and inorganic hydroiodic acid. Doesn't form water hydrates.


Reaction between potassium or sodium iodide and lead(II) acetate or nitrate

Chemical equation:

Pb(CH3COO)2 + 2KI = 2KCH3COO + PbI2
Pb(CH3COO)2 + 2NaI = 2NaCH3COO + PbI2
Pb(NO3)2 + 2KI = 2KNO3 + PbI2
Pb(NO3)2 + 2NaI = 2NaNO3 + PbI2

For preparation of 100.00g of lead(II) iodide а 71.85g of lead(II) nitrate or 82.28g of lead(II) acetate trihydrate and 72.02g of potassium iodide or 65.03g of sodium iodide is required.
Take two plastic or glass containers connected with a tube at center or bottom. Connection should be hermetic.

Place silicic acid gel in the tube.
Then add solution of lead(II) nitrate or acetate to the first container and potassium or sodium iodide to the another one. Pour solutions simultaneously otherwise gel will pour out from tube. Cover containers with a cap (you can leave them non-hermetic) and leave for long time at room temperature.
During long time reagents will slowly diffuse deeper into the thickness the gel, reacts with small parts if meeting. A slow crystal growing of the slight soluble reaction product will begin.


There are few appropriate methods of growing:

  • Cooling the hot solution of the final compound
  • Direct reaction with simultaneous cooling (general method, the basis of experiment called "Golden rain")
  • Carrying out the reaction in the gel of silicic acid

Storage conditions

Store in its original form or under several layers of varnish at average humidity and room temperature. Do not store in matchboxes or cotton wool and do not heat.


Temperatureгр/100,00 гр waterгр/100,00 гр acetoneгр/100,00 гр anilineгр/100,00 гр pyridineгр/100,00 гр formic acid 95%гр/100,00 гр hydrazine
0°C273.15 K <br />32 °F <br />491.67 °R <br />0.040.2
10°C283.15 K <br />50 °F <br />509.67 °R <br />0.0560.205
15°C288.15 K <br />59 °F <br />518.67 °R <br />0.0610.50.208
20°C293.15 K <br />68 °F <br />527.67 °R <br />0.076~0.200.252
25°C298.15 K <br />77 °F <br />536.67 °R <br />~0.08~0.19
30°C303.15 K <br />86 °F <br />545.67 °R <br />0.090.188
40°C313.15 K <br />104 °F <br />563.67 °R <br />0.124~0.21
50°C323.15 K <br />122 °F <br />581.67 °R <br />~0.16~0.23
60°C333.15 K <br />140 °F <br />599.67 °R <br />0.1930.02~0.25
70°C343.15 K <br />158 °F <br />617.67 °R <br />~0.24~0.27
80°C353.15 K <br />176 °F <br />635.67 °R <br />0.294~0.29
90°C363.15 K <br />194 °F <br />653.67 °R <br />~0.37~0.32
100°C373.15 K <br />212 °F <br />671.67 °R <br />0.4360.34
Highly soluble in ammonia. Slightly soluble in methyl acetate and benzonitrile. Insoluble in ethanol, carbon disulfide and ethyl acetate.