PbS
lead(II) sulfide · lead sulfide, galena, lead monosulfide, plumbous sulfide
PbS is lead(II) sulfide, a narrow-gap semiconductor made of lead and sulfur. It occurs in nature as the mineral galena. It is thermodynamically stable and has the cubic rock-salt crystal structure at ambient conditions. It is an important material for infrared optoelectronics and is being studied for thermoelectric energy conversion.
About lead(II) sulfide
What is PbS and what structure does it adopt?
PbS is lead(II) sulfide. Its mineral form, galena, is the main natural ore of lead. At ambient temperature and pressure it crystallizes in the cubic rock-salt (halite, B1) structure with space group Fm-3m. Lead and sulfur sit on two interpenetrating face-centred cubic sublattices, and each atom has regular octahedral coordination. Under elevated hydrostatic pressure, PbS changes to an orthorhombic phase. It is the stable compound of the lead–sulfur system.
What is PbS used for?
PbS has a long history in infrared detection. Bulk and thin-film PbS is widely used in photoconductive infrared photodetectors that are sensitive in the near-infrared and short-wave infrared. Colloidal PbS quantum dots are being studied for solution-processed photodetectors, infrared imagers and photovoltaics, because their absorption edge can be tuned by changing the dot size. In thermoelectrics, PbS is studied as an earth-abundant, lower-cost alternative to tellurium-based materials for recovering waste heat, both on its own and in alloys and composites. Historically, natural galena crystals served as point-contact (cat's-whisker) rectifiers in early crystal radio detectors.
How stable and synthesizable is PbS?
PbS is thermodynamically stable under ambient conditions, which is consistent with how common galena is in nature. Crystalline PbS can be made by direct reaction of the elements, by vapour transport, or as thin films by chemical bath deposition. Colloidal nanocrystals are routinely made by solution routes at mild temperatures. Small departures from stoichiometry matter: excess lead makes PbS n-type and excess sulfur makes it p-type. Handling it requires precautions because lead compounds are toxic to people and the environment.
Is PbS a semiconductor, and what does that imply?
Yes. PbS is a direct narrow-gap semiconductor, with its band gap at the L point of the Brillouin zone. Like the other lead chalcogenides, it has a high dielectric permittivity and high carrier mobilities. The small gap gives strong optical absorption across the near-infrared, which is why it works well in photodetectors. Its large exciton Bohr radius means quantum confinement widens the gap even in relatively large nanocrystals. For thermoelectric use, its carrier type and concentration can be controlled by n-type or p-type doping.
How does PbS compare with PbSe and PbTe?
PbS, PbSe and PbTe are isostructural rock-salt IV–VI semiconductors with narrow band gaps. Compared with PbSe and PbTe, PbS has a higher lattice thermal conductivity and a higher effective mass, which makes binary PbS a weaker thermoelectric. PbTe is the benchmark for mid-temperature thermoelectrics. PbS's main advantage is that sulfur is much more abundant and cheaper than tellurium. Alloying PbS with cadmium sulfide raises the band gap above that of pure PbS.
Key Properties
Cross-validated computational properties for lead(II) sulfide, aggregated across 5 databases.
Band GapEnergy needed to move an electron from the valence band to the conduction band. Lower or zero values tend to behave more metallic; larger gaps are more insulating or semiconducting.
Energy Above HullThermodynamic distance from the most stable set of competing phases. 0 eV/atom is on the convex hull; small positive values may still be experimentally accessible.
StabilityA plain-language summary of the best reported energy-above-hull result. It reflects whether the lowest-energy structure is on, near, or far from the stability hull.
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of PbS. Tight agreement means computed properties can be trusted without re-running calculations.
Agreement ScoreA normalized confidence score summarizing how closely independent DFT databases agree. Higher scores mean tighter cross-source agreement.
Hull SpreadDifference between the highest and lowest energy-above-hull values reported by comparable sources. Smaller spread means less thermodynamic disagreement.
Sources ComparedNumber and names of computational sources with comparable entries for this formula.
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
Reported Structures
Lowest-energy structures reported for PbS, ranked by energy above hull.
| Space GroupSymmetry classification of the crystal arrangement. The number is the international space-group index. | Crystal SystemBroad lattice family, such as cubic, tetragonal, monoclinic, or triclinic, derived from unit-cell symmetry. | Band Gap (eV)Electronic gap calculated for this specific reported structure, measured in electronvolts. | E above hull (eV/atom)Thermodynamic distance from the convex hull for this structure, normalized per atom. Lower is generally more stable. | E/atom (eV)Computed total energy normalized per atom. Use energy above hull, not this value alone, when comparing stability. | Density (g/cm³)Mass per relaxed crystal volume, reported in grams per cubic centimeter. |
|---|---|---|---|---|---|
| I4/mmm (No. 139) | tetragonal | 1.29 | 0.0000 | -0.656 | — |
| — | — | 0.69 | 0.0000 | -0.685 | — |
| Fm-3m (No. 225) | cubic | 0.47 | 0.0000 | -4.709 | 7.45 |
| I4/mmm (No. 139) | tetragonal | 1.29 | 0.0001 | -0.656 | — |
| I4/mmm (No. 139) | tetragonal | 1.29 | 0.0001 | -0.656 | — |
| — | — | 0.60 | 0.0002 | -0.685 | — |
| — | — | 0.52 | 0.0006 | -0.684 | — |
| R3m (No. 160) | trigonal | 0.56 | 0.0014 | -4.708 | 7.44 |
| Fm-3m (No. 225) | cubic | 0.76 | 0.0124 | -0.644 | — |
| Fm-3m (No. 225) | cubic | 0.72 | 0.0124 | -0.644 | — |
| Fm-3m (No. 225) | cubic | 0.84 | 0.0125 | -0.643 | — |
| Fm-3m (No. 225) | cubic | 0.50 | 0.0132 | -0.643 | — |
Synthesis Routes
Literature-extracted synthesis procedures targeting PbS.
Applications
Where lead(II) sulfide is used.
Patent Landscape
1 patent reference PbS or close compositional variants.
| Patent | Title | Assignee | Granted |
|---|---|---|---|
| 4029853 | PbS-Al selective solar absorber | — | — |
Frequently Asked Questions
Common questions about lead(II) sulfide, answered from cross-validated data and the published literature.
Is PbS the same as galena?
Yes. Galena is the naturally occurring mineral form of lead(II) sulfide (PbS), and it is the main ore mined for lead.
What crystal structure does PbS adopt at ambient conditions?
Why is PbS used in infrared photodetectors?
Does PbS undergo phase transitions under pressure?
What advantage does PbS offer over PbTe in thermoelectric research?
What is PbS?
What is PbS used for?
What is the band gap of PbS?
Is PbS a metal, semiconductor, or insulator?
Is PbS thermodynamically stable?
What is the crystal structure of PbS?
What is the density of PbS?
How many polymorphs of PbS are known?
How is PbS synthesized?
What elements does PbS contain?
Where does the data for PbS come from?
Related Compounds
Other Lead Chalcogenide Thermoelectrics in the database.
Data sources & attribution
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- oqmd — Data from the OQMD (oqmd.org). Cite: Saal et al., JOM 65, 1501 (2013); Kirklin et al., npj Comp. Mater. 1, 15010 (2015). (CC-BY-4.0)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
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