Lead(II) sulfide

Addition of hydrogen sulfide or sulfide salts to a solution containing a lead salt, such as PbCl₂, gives a black precipitate of lead sulfide.

: Pb²⁺ + H₂S → PbS↓ + 2 H⁺

This reaction is used in qualitative inorganic analysis. The presence of hydrogen sulfide or sulfide ions may be tested using "lead acetate paper."

Like the related materials PbSe and PbTe, PbS is a semiconductor.{{cite book|author1=Vaughan, D. J. |author2=Craig, J. R. |title=Mineral Chemistry of Metal Sulfides|publisher= Cambridge University Press|location= Cambridge|year= 1978|isbn=978-0-521-21489-6}}; In fact, lead sulfide was one of the earliest materials to be used as a semiconductor.Hogan, C. Michael (2011). [http://www.eoearth.org/article/Sulfur?topic=49557 "Sulfur"]. in Encyclopedia of Earth, eds. A. Jorgensen and C.J. Cleveland, National Council for Science and the environment, Washington DC. {{webarchive|url=https://web.archive.org/web/20121028080550/http://www.eoearth.org/article/Sulfur?topic=49557 |date=2012-10-28 }} Lead sulfide crystallizes in the sodium chloride motif, unlike many other IV-VI semiconductors.

Since PbS is the main ore of lead, much effort has focused on its conversion. A major process involves smelting of PbS followed by reduction of the resulting oxide. Idealized equations for these two steps are:{{cite book|author1=Sutherland, Charles A. |author2=Milner, Edward F. |author3=Kerby, Robert C. |author4=Teindl, Herbert |author5=Melin, Albert |author6=Bolt, Hermann M. |chapter=Lead|title= Ullmann's Encyclopedia of Industrial Chemistry|year= 2005 |publisher=Wiley-VCH|location= Weinheim|doi=10.1002/14356007.a15_193.pub2|isbn=978-3527306732 }}

: 2 PbS + 3 O₂ → 2 PbO + 2 SO₂

: PbO + C → Pb + CO

The sulfur dioxide is converted to sulfuric acid.

Lead sulfide-containing nanoparticle and quantum dots have been well studied.{{Cite journal|title = The Quantum Mechanics of Larger Semiconductor Clusters ("Quantum Dots")|journal = Annual Review of Physical Chemistry|date = 1990-01-01|pages = 477–496|volume = 41|issue = 1|doi = 10.1146/annurev.pc.41.100190.002401|first3 = L. E.|last3 = Brus|bibcode = 1990ARPC...41..477B}} Traditionally, such materials are produced by combining lead salts with a variety of sulfide sources.{{Cite journal|title = Coated semiconductor nanoparticles; the cadmium sulfide/lead sulfide system's synthesis and properties|journal = The Journal of Physical Chemistry|date = 2002-05-01|pages = 895–901|volume = 97|issue = 4|doi = 10.1021/j100106a015|language = EN|first1 = H. S.|last1 = Zhou|first2 = I.|last2 = Honma|first3 = H.|last3 = Komiyama|first4 = Joseph W.|last4 = Haus}}{{Cite journal|title = A novel and simple one-step solid-state reaction for the synthesis of PbS nanoparticles in the presence of a suitable surfactant|journal = Materials Research Bulletin|date = 2001-09-15|pages = 1977–1984|volume = 36|issue = 11|doi = 10.1016/S0025-5408(01)00678-X|first1 = Wenzhong|last1 = Wang|first2 = Yingkai|last2 = Liu|first3 = Yongjie|last3 = Zhan|first4 = Changlin|last4 = Zheng|first5 = Guanghou|last5 = Wang}} In 2009, PbS nanoparticles have been examined for use in solar cells.{{Cite journal|title = PbS and CdS Quantum Dot-Sensitized Solid-State Solar Cells: "Old Concepts, New Results"|journal = Advanced Functional Materials|date = 2009-09-09|issn = 1616-3028|pages = 2735–2742|volume = 19|issue = 17|doi = 10.1002/adfm.200900081|language = en|first1 = HyoJoong|last1 = Lee|first2 = Henry C.|last2 = Leventis|first3 = Soo-Jin|last3 = Moon|first4 = Peter|last4 = Chen|first5 = Seigo|last5 = Ito|first6 = Saif A.|last6 = Haque|first7 = Tomas|last7 = Torres|first8 = Frank|last8 = Nüesch|first9 = Thomas|last9 = Geiger| s2cid=98631978 |doi-access = free}}

File:CatWhisker.jpg used in the early 1900s]]

File:German WWII PbS IR detector.jpg

{{See also|Photoconductivity}}

PbS was one of the first materials used for electrical diodes that could detect electromagnetic radiation, including infrared light.{{cite journal |doi=10.1088/0370-1301/64/7/110 |title=Lead Sulphide – An Intrinsic Semiconductor |year=1951 |author=Putley, E H |journal=Proceedings of the Physical Society | series = Series B | volume=64 |issue=7 |pages=616–618 |last2=Arthur |first2=J B|author-link=E. H. Putley }} As an infrared sensor, PbS directly detects light, as opposed to thermal detectors, which respond to a change in detector element temperature caused by the radiation. A PbS element can be used to measure radiation in either of two ways: by measuring the tiny photocurrent the photons cause when they hit the PbS material, or by measuring the change in the material's electrical resistance that the photons cause. Measuring the resistance change is the more commonly used method. At room temperature, PbS is sensitive to radiation at wavelengths between approximately 1 and 2.5 μm. This range corresponds to the shorter wavelengths in the infra-red portion of the spectrum, the so-called short-wavelength infrared (SWIR). Only very hot objects emit radiation in these wavelengths.

Cooling the PbS elements, for example using liquid nitrogen or a Peltier element system, shifts its sensitivity range to between approximately 2 and 4 μm. Objects that emit radiation in these wavelengths still have to be quite hot—several hundred degrees Celsius—but not as hot as those detectable by uncooled sensors. (Other compounds used for this purpose include indium antimonide (InSb) and mercury-cadmium telluride (HgCdTe), which have somewhat better properties for detecting the longer IR wavelengths.) The high dielectric constant of PbS leads to relatively slow detectors (compared to silicon, germanium, InSb, or HgCdTe).

Elevations above 2.6 km (1.63 mi) on the planet Venus are coated with a shiny substance. Though the composition of this coat is not entirely certain, one theory is that Venus "snows" crystallized lead sulfide much as Earth snows frozen water. If this is the case, it would be the first time the substance was identified on a foreign planet. Other less likely candidates for Venus' "snow" are bismuth sulfide and tellurium.{{cite news|url=http://news-info.wustl.edu/news/page/normal/633.html|access-date=2009-07-07|title='Heavy metal' snow on Venus is lead sulfide|publisher=Washington University in St. Louis|archive-date=2008-04-15|archive-url=https://web.archive.org/web/20080415000214/http://news-info.wustl.edu/news/page/normal/633.html|url-status=live}}

Lead(II) sulfide is so insoluble that it is almost nontoxic, but pyrolysis of the material, as in smelting, gives dangerous toxic fumes of lead and oxides of sulfur.{{Cite web |url=http://www.espimetals.com/msds%27s/leadsulfide.pdf |title=Lead sulfide MSDS |access-date=2009-11-20 |archive-url=https://web.archive.org/web/20061111080525/http://www.espimetals.com/msds's/leadsulfide.pdf |archive-date=2006-11-11 |url-status=dead }} Lead sulfide is insoluble and a stable compound in the pH of blood and so is probably one of the less toxic forms of lead.{{cite journal |url=https://jpet.aspetjournals.org/content/34/1/85|title=Studies on the Toxicity of Various Lead Compounds Given Intravenously |author1=Bischoff, Fritz |author2=Maxwell, L. C. |author3=Evens, Richard D. |author4=Nuzum, Franklin R. |journal=Journal of Pharmacology and Experimental Therapeutics |year=1928 |volume=34 |issue=1 |pages=85–109 }} A large safety risk occurs in the synthesis of PbS using lead carboxylates, as they are particularly soluble and can cause negative physiological conditions.

{{reflist|30em}}

• {{cite book |ref=Haynes| editor= Haynes, William M. | date = 2016| title = CRC Handbook of Chemistry and Physics | edition = 97th | publisher = CRC Press | isbn = 9781498754293}}

{{Commons category|Lead(II) sulfide}}

• [https://www.atsdr.cdc.gov/csem/csem.html Case Studies in Environmental Medicine (CSEM): Lead Toxicity]
• [https://www.atsdr.cdc.gov/toxfaqs/tfacts13.pdf ToxFAQs: Lead]
• [https://web.archive.org/web/20080111154608/http://www.npi.gov.au/database/substance-info/profiles/50.html National Pollutant Inventory – Lead and Lead Compounds Fact Sheet]

{{Lead compounds}}

{{Sulfides}}

{{DEFAULTSORT:Lead(Ii) Sulfide}}

Category:Lead(II) compounds

Category:Monosulfides

Category:IV-VI semiconductors

Category:Infrared sensor materials

Category:Rock salt crystal structure