Lead(II) iodide

Lead(II) iodide
Names
Other names
Plumbous iodide
Identifiers
10101-63-0 YesY
ChemSpider 23305 YesY
Jmol 3D model Interactive image
PubChem 167719
UNII OTL90F2GLT YesY
Properties
PbI2
Molar mass 461.01 g/mol
Appearance bright yellow powder
Odor odorless
Density 6.16 g/cm3
Melting point 402 °C (756 °F; 675 K)
Boiling point 953 °C (1,747 °F; 1,226 K)
0.044 g/100 mL (0 °C)
0.0756 g/100 mL (20 °C)[1]
0.41 g/100 mL (100 °C)[2]
4.41 x 10−9 (20 °C)
Solubility insoluble in ethanol, cold HCl
soluble in alkalis, KI solution
Band gap 2.3 eV
Structure
Rhombohedral,hexagonal hP3
P-3m1, No. 164
octahedral
Hazards
Repr. Cat. 1/3
Harmful (Xn)
Dangerous for the environment (N)
R-phrases R61, R20/22, R33, R62, R50/53
S-phrases S53, S45, S60, S61
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
0
3
0
Flash point Non-flammable
Related compounds
Other anions
 Lead(II) fluoride
Lead(II) chloride
Lead(II) bromide
Other cations
 Tin(II) iodide
Related compounds
 Thallium(I) iodide
Bismuth(III) iodide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
Infobox references

Lead (II) Iodide Lead iodide, lead diiodide, or Plumbous iodide with the formula PbI2 is often sold in a powder or crystal form and has a formula weight of 461.01g/mol. It is an ionic compound, consisting of two halogens (iodide) and one post-transition metal (lead). Following chemical solubility rules, it is insoluble in water and also denser than water. It has very high melting and boiling points of 402°C and 954°C respectively. It is extremely hazardous to human health (due to the lead content) as well as the aquatic environment. It’s color ranges from yellow, to yellow-orange, to orange-brown. It is also odorless and non-combustible.[3]

Preparation

PbI2 is commonly synthesized via a double displacement reaction between Potassium iodide (KI) and Lead nitrate (Pb(NO3)2) as shown below. The KNO3 is soluble and the PbI2 insoluble and thus a yellow precipitate is formed. [4]

Pb(NO3)2 + 2KI → PbI2 + 2KNO3

Car Battery Synthesis: PbI2 has also been synthesized from lead car batteries. The battery provided a source of lead which was processed and diluted in acetic acid to release Pb2+ ions which were then reacted with KI to precipitate out PbI2. The purity of the battery produced PbI2 was lower than that of a commercially available product but the process still produced the correct substance.[5]

Outer Space Synthesis: PbI2 crystals have also been synthesized in space utilizing a plexiglass chamber with a cellulose membrane to separate solutions of Lead (II) acetate and KI. The lead and KI diffused across the membrane and crystal growth occurred. These crystals were compared to earth grown crystals and they were found to have a higher purity and also resulted in a higher percent yield.[6]

Chemical Vapor Deposition: PbI2 crystals can also be synthesized from PbI2 powder placed in a quartz tube. On the other end of the quartz tube, mica washed with acetone was added and oxygen was removed from the tube and replaced with a Ar and H2 gas mixture. The tube was then heated to 380° and then cooled to produce regular crystals.[7]

Bridgman-Stockbarger: The Bridgman-Stockbarger technique is often utilized to grow PbI2 crystals. It involves heating previously synthesized PbI2 past its melting point and then passing the ampule through a temperature gradient to produce the crystals.


Application and Use

PbI2 has been found to be particularly useful in perovskite solar cells. The PbI2 compound acts as the light capturing part of the solar cell and has been found to increase the efficiency of the cell. Once PbI2 crystals have been synthesized, they are turned into a thin film and then spin coated with methylammonium iodide. The yellow color of PbI2 will change to light brown which indicates that the PbI2 has been converted to perovskite methylammonium lead iodide which can then be used in solar cells.[5]

Apart from its use as a starting material in solar cells, PbI2 is used in some areas of art such as bronzing and photography.[3] It used to be utilized as a paint pigment known as iodine yellow but due to the instability of the compound it is no longer used as such.[8] PbI2 is also used as a high-energy photon detector for those emitted by gamma and X-rays.[3] Lead iodide is a good X-ray detector as it has a wide band gap which ensures low noise operation.[9]

History

PbI2 was first used as a pigment in paint, it was described by Prosper Merimee (1830) as “ not yet much known in commerce, is as bright as orpiment or chromate of lead. It is thought to be more permanent; but time only can prove its pretension to so essential a quality. It is prepared by precipitating a solution of acetate or nitrate of lead, with hydrochlorate of potassium: the nitrate produces a more brilliant yellow color.”[8]

Toxicity

Due to the obvious lead content in lead Iodide, the substance is highly toxic to human health. Exposure to lead, even in small amounts, is extremely dangerous to the body particularly the nervous, hematopoetic, renal, and hepatic systems. Lead mainly harms the body by creating an imbalance between the production of free radicals and the bodies ability to repair free radical damage. Most of the lead that enters the body gets stored in the bones and then later released back into the bloodstream.[10] Lead paint and leaded pipes are two of the most common ways that lead enters the environment and eventually the body.[11] Lead iodide has been found to be a carcinogen in animals suggesting the same may hold true in humans.[12]

Structure

Characterization of the structure of PbI2 crystals using X-ray powder diffraction (XRD) has been found to be primarily hexagonal, however it can also take up a rhombohedral structure as well.[13][14] Lead iodid also follows a hexagonally closest packed system meaning it alternates between layers of lead atoms and iodide atoms, bonding between atoms in the layers is largely ionic.[7] Weak Van der Waals interactions have been observed between lead-iodide layers.[9] Oxidic impurities can affect PbI2 crystals but it has been shown that melting refinement under a H2 gas environment can reduce these impurities.[15]


Lead(II) iodide precipitates when solutions of potassium iodide and lead(II) nitrate are combined
Experiment "golden rain" where iodide of lead (II) was recrystallized from hot solution by cooling, forming crystals of golden-yellow.

See also

References

  1. ↑ NIST-data review 1980
  2. ↑ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
  3. 1 2 3 "Lead(II) iodide 99% | Sigma-Aldrich". www.sigmaaldrich.com. Retrieved 2016-04-29.
  4. ↑ Ahmad, Shahab; Prakash, G Vijaya (2012-12-09). "Fabrication of excitonic luminescent inorganic-organic hybrid nano and microcrystals". International Conference on Fibre Optics and Photonics (Optical Society of America). doi:10.1364/photonics.2012.mpo.40.
  5. 1 2 Dhiaputra, Ilham; Permana, Bayu; Maulana, Yusep; Inayatie, Yuniar Dwi; Purba, Yonatan R.; Bahtiar, Ayi (2016-02-24). "Composition and crystal structure of perovskite films attained from electrodes of used car battery". AIP Conference Proceedings (AIP Publishing) 1712: 050013. doi:10.1063/1.4941896.
  6. ↑ Scaife, Charles W. J.; Cavoli, S. Richard; Blanton, Thomas N.; Morse, Mark D.; Sever, Byron R.; Willis, William S.; Suib, Steven L. (1990-11-01). "Synthesis and characterization of lead(II) iodide grown in space". Chemistry of Materials 2 (6): 777–780. doi:10.1021/cm00012a034. ISSN 0897-4756.
  7. 1 2 Liu, Xinfeng; Ha, Son Tung; Zhang, Qing; de la Mata, Maria; Magen, César; Arbiol, Jordi; Sum, Tze Chien; Xiong, Qihua (2015-01-27). "Whispering Gallery Mode Lasing from Hexagonal Shaped Layered Lead Iodide Crystals". ACS Nano 9 (1): 687–695. doi:10.1021/nn5061207. ISSN 1936-0851.
  8. 1 2 Eastaugh, Nicholas (2004). The Pigment Compendium: a Dictionary of Historical Pigments. Amsterdam: Elsevier Butterworth-Heinemann.
  9. 1 2 Shah, K. S; Olschner, F; Moy, L. P; Bennett, P; Misra, M; Zhang, J; Squillante, M. R; Lund, J. C (1996-10-01). "Lead iodide X-ray detection systems". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. Proceedings of the 9th International Workshop on Room Temperature Semiconductor X- and γ-Ray Detectors, Associated Electronics and Applications 380 (1–2): 266–270. doi:10.1016/S0168-9002(96)00346-4.
  10. ↑ Flora, Gagan; Gupta, Deepesh; Tiwari, Archana. "Toxicity of lead: a review with recent updates". Interdisciplinary Toxicology 5 (2). doi:10.2478/v10102-012-0009-2. ISSN 1337-9569. PMC 3485653. PMID 23118587.
  11. ↑ Patrick, L. (2006). "Lead toxicity, a review of the literature. Part I: exposure, evaluation, and treatment.,". Alternative Medicine Review.
  12. ↑ "Haz-Map Category Details". hazmap.nlm.nih.gov. Retrieved 2016-04-29.
  13. ↑ Bhavsar, D. "Structural studies of vacuum evaporated Lead Iodide Thin Films, Advances In Applied Science Research" (PDF). Applied Science.
  14. ↑ Hassan, Mahmoud A.; Jafar, Mousa M.; Matuchova, Marie; Bulos, Basim N. "An Experimental Evidence of some Lead Iodide Polytypes Compatible with the Dielectric Functions Model". Journal of Applied Sciences 10 (24): 3367–3373. doi:10.3923/jas.2010.3367.3373.
  15. ↑ Tonn, J.; Matuchova, M.; Danilewsky, A. N.; Cröll, A. (2015-04-15). "Removal of oxidic impurities for the growth of high purity lead iodide single crystals". Journal of Crystal Growth 416: 82–89. doi:10.1016/j.jcrysgro.2015.01.024.
  16. Sigma-Aldrich: Analytical, Biology, Chemistry & Materials Science products and services. Sigma-Aldrich, http://www.sigmaaldrich.com/catalog/product/aldrich/211168?lang=en®ion=us (accessed Apr 8, 2016).
  17. Ahmad, S.; Prakash, G. V. Fabrication Of Excitonic Luminescent Inorganic-Organic Hybrid Nano and Microcrystals. International Conference on Fibre Optics and Photonics. 2012.
  18. Dhiaputra, I.; Permana, B.; Maulana, Y.; Inayatie, Y. D.; Purba, Y. R.; Bahtiar, A. Composition And Crystal Structure of Perovskite Films Attained from Electrodes of Used Car Battery. American Institute of Physics. 2016.
  19. Scaife, C. W. J.; Cavoli, S. R.; Blanton, T. N.; Morse, M. D.; Sever, B. R.; Willis, W. S.; Suib, S. L. Synthesis And Characterization of Lead(II) Iodide Grown in Space. Chemistry of Materials Chem. Mater. 1990, 2, 777–780.
  20. X. Liu, S.T. Ha, Q. Zhang, M.D.L. Mata, C. Magen, J. Arbiol, et al., Whispering Gallery Mode Lasing from Hexagonal Shaped Layered Lead Iodide Crystals, ACS Nano. 9 (2015) 687–695. doi:10.1021/nn5061207.
  21. Estaugh, N. The Pigment Compendium: a Dictionary of Historical Pigments; Elsevier Butterworth-Heinemann: Oxford, 2004.
  22. Lead in History. Corrosion science and engineering information hub, http://corrosion-doctors.org/ (accessed Apr 8, 2016).
  23. G. Flora, D. Gupta, A. Tiwari, Toxicity of lead: a review with recent updates, Interdisciplinary Toxicology. 5 (2012). doi:10.2478/v10102-012-0009-2.
  24. L. Patrick, Lead toxicity, a review of the literature. Part I: exposure, evaluation, and treatment., Alternative Medicine Review. (2006).
  25. D.S. Bhavsar, Structural studies of vacuum evaporated Lead Iodide Thin Films, Advances In Applied Science Research. 2 (2011) 407–413. http://pelagiaresearchlibrary.com/advances-in-applied-science/vol2-iss2/adasr-2011-2-2-407-413.pdf.
  26. Haz-Map, Category Details. (n.d.). https://hazmap.nlm.nih.gov/category-details?id=2524 (accessed April 27, 2016).
  27. M.A. Hassan, M.M. Jafar, M. Matuchova, B.N. Bulos, An Experimental Evidence of some Lead Iodide Polytypes Compatible with the Dielectric Functions Model, Journal Of Applied Sciences J. of Applied Sciences. 10 (2010) 3367–3373. doi:10.3923/jas.2010.3367.3373.
  28. J. Tonn, M. Matuchova, A. Danilewsky, A. Cröll, Removal of oxidic impurities for the growth of high purity lead iodide single crystals, Journal Of Crystal Growth. 416 (2015) 82–89. doi:10.1016/j.jcrysgro.2015.01.024.

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