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| Names | |
|---|---|
| Other names Plumbous sulfide Galena, Sulphuret of lead | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider |
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| ECHA InfoCard | 100.013.861 |
| EC Number |
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| RTECS number |
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| UNII | |
| UN number | 3077 |
| |
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| Properties | |
| PbS | |
| Molar mass | 239.30 g/mol |
| Appearance | Black |
| Density | 7.60 g/cm3[1] |
| Melting point | 1,113[1] °C (2,035 °F; 1,386 K) |
| Boiling point | 1,281 °C (2,338 °F; 1,554 K) |
| 2.6×10−11 kg/kg (calculated, at pH=7)[2] 8.6×10−7 kg/kg[3] | |
| −83.6·10−6 cm3/mol[4] | |
Refractive index (nD) | 3.91[5] |
| Structure[7] | |
| Halite (cubic),cF8 | |
| Fm3m, No. 225 | |
a = 5.936 Å | |
Formula units (Z) | 4 |
| Octahedral (Pb2+) Octahedral (S2−) | |
| 3.59 D[6] | |
| Thermochemistry[8] | |
| 49.5 J/mol⋅K | |
Std molar entropy(S⦵298) | 91.2 J/mol |
Std enthalpy of formation(ΔfH⦵298) | −100.4 kJ/mol |
Gibbs free energy(ΔfG⦵) | −98.7 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) | |
| Flash point | Non-flammable |
| Safety data sheet (SDS) | External MSDS |
| Related compounds | |
Otheranions | Lead(II) oxide Lead selenide Lead telluride |
Othercations | Carbon monosulfide Silicon monosulfide Germanium(II) sulfide Tin(II) sulfide |
Related compounds | Thallium sulfide Lead(IV) sulfide Bismuth sulfide |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Lead(II) sulfide (also spelledsulphide) is aninorganic compound with theformulaPbS.Galena is the principal ore and the most important compound oflead. It is a semiconducting material with niche uses.
Addition ofhydrogen sulfide or sulfide salts to a solution containing a lead salt, such as PbCl2, gives a black precipitate of lead sulfide.
This reaction is used inqualitative inorganic analysis. The presence of hydrogen sulfide or sulfide ions may be tested using "lead acetate paper."
Like the related materialsPbSe andPbTe, PbS is asemiconductor.[9] In fact, lead sulfide was one of the earliest materials to be used as a semiconductor.[10] Lead sulfide crystallizes in thesodium chloride motif, unlike many otherIV-VI semiconductors.
Since PbS is the main ore of lead, much effort has focused on its conversion. A major process involvessmelting of PbS followed by reduction of the resultingoxide. Idealized equations for these two steps are:[11]
Thesulfur dioxide is converted tosulfuric acid.
Lead sulfide-containingnanoparticle andquantum dots have been well studied.[12] Traditionally, such materials are produced by combining lead salts with a variety of sulfide sources.[13][14] In 2009, PbS nanoparticles have been examined for use in solar cells.[15]
PbS was one of the first materials used for electrical diodes that could detect electromagnetic radiation, includinginfrared light.[16] 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 tinyphotocurrent the photons cause when they hit the PbS material, or by measuring the change in the material'selectrical resistance that the photons cause. Measuring the resistance change is the more commonly used method. Atroom temperature, PbS is sensitive to radiation atwavelengths between approximately 1 and 2.5μm. This range corresponds to the shorter wavelengths in the infra-red portion of thespectrum, 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 aPeltier element system, shifts its sensitivity range to between approximately 2 and 4μm. Objects that emit radiation in these wavelengths still have to be quite hot—several hundred degreesCelsius—but not as hot as those detectable by uncooled sensors. (Other compounds used for this purpose includeindium antimonide (InSb) andmercury-cadmium telluride (HgCdTe), which have somewhat better properties for detecting the longer IR wavelengths.) The highdielectric constant of PbS leads to relatively slow detectors (compared tosilicon,germanium, InSb, or HgCdTe).
In 2008 it was reported that elevations above 2.6 km (1.63 mi) on theplanetVenus 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 asEarth 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" arebismuth sulfide andtellurium.[17]
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.[18] 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.[19] A large safety risk occurs in the synthesis of PbS using lead carboxylates, as they are particularly soluble and can causenegative physiological conditions.
