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Lead(II) sulfide
Lead(II) sulfide
Other names plumbous sulfide, galena
Identifiers
CAS number [1314-87-0]
Properties
Molecular formula PbS
Molar mass 239. CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Molar mass, symbol M, is the Mass of one mole of a substance ( Chemical element or Chemical compound) 28 g/mol
Density 7700 kg/m3
Melting point

1390 K
Boiling point

1281°C
Solubility in other solvents Insoluble
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references

Lead sulfide (also spelled sulphide, see Sulfur#Spelling) is a chemical compound PbS, most often purified from the mineral galena. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different The melting point of a solid is the temperature range at which it changes state from solid to Liquid. The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. In Chemistry, the standard state of a material is its state at 1 bar (100 Kilopascals exactly Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 A chemical compound is a substance consisting of two or more different elements chemically bonded together in a fixed proportion by Mass. Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific Galena is the natural mineral form of Lead sulfide. It is the most important Lead Ore mineral PbS, PbSe and PbTe lead salts are semiconductors of the IV-VI family. Lead selenide () or lead(II selenide, a Selenide of Lead, is a Semiconductor material. Lead telluride is a compound of lead and Tellurium (PbTe it is a Narrow gap semiconductor. A semiconductor' is a Solid material that has Electrical conductivity in between a conductor and an insulator; it can vary over that Lead sulfide is toxic due to the lead content, see lead poisoning. Lead poisoning (also known as saturnism, plumbism, or painter's colic) is a medical condition caused by increased levels of the metal Lead in

Contents

Applications

Lead sulfide and several other lead compounds are used as detection element material in various infra-red sensors. Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of Of these, PbS (lead sulfide) is one of the oldest and most commonly used. The term sulfide ( sulphide in British English) refers to several types of Chemical compounds containing Sulfur in its lowest Oxidation It is used for eg. infrared detectors. An infrared detector is a Photodetector that reacts to Infrared (IR Radiation.

When used for infrared, these detection element are classified as photon detectors: unlike thermal detectors (the other major type), IR detectors respond directly to the incident radiation. In Physics, the photon is the Elementary particle responsible for electromagnetic phenomena A thermal column (or thermal) is a column of rising Air in the lower altitudes of the Earth's atmosphere. Thermal detectors respond only to the material's temperature change caused by the energy from the photons. Because of this difference, radiation can then be measured in two ways, either by detecting the tiny photocurrent or by measuring the change in the materials electrical resistance. Electric current is the flow (movement of Electric charge. The SI unit of electric current is the Ampere. Electrical resistance is a ratio of the degree to which an object opposes an Electric current through it measured in Ohms Its reciprocal quantity is Measuring the resistance change is the more commonly used method.

At room temperature, PbS elements are sensitive to radiation at wavelengths between approximately 1 and 2. Room temperature (also referred to as ambient temperature) is a common term to denote a certain Temperature within enclosed space at which humans are accustomed In Physics wavelength is the distance between repeating units of a propagating Wave of a given Frequency. 5 μm. A micrometre ( American spelling: micrometer; symbol µm) is one millionth of a Metre, or equivalently one thousandth of a Millimetre This range corresponds to the shorter wavelengths in the IR band, and is called near-IR, a term which refers to the fact that it is close to the wavelengths of visible light. A band is a small section of the spectrum of Radio communication frequencies, in which channels are usually used or set aside for the same Only very hot objects emit radiation in these wavelengths.

Cooling the PbS elements, for example using pressurised or liquified gas or a Peltier element system shifts its sensitivity range to between approximately 2 and 4 μm. The thermoelectric effect is the direct conversion of temperature differences to electric Voltage and vice versa Objects which emit radiation in these wavelengths still have to be quite hot; several hundred degrees Celsius; but not as hot as those which are detectable by uncooled sensors. The Celsius Temperature scale was previously known as the centigrade scale.

Other compounds used for this purpose include indium antimonide (InSb) and HgCdTe, which have somewhat better properties for detecting the longer IR wavelengths. Indium antimonide ( is a Narrow gap Semiconductor material from the III - V group used in Infrared detectors including Thermal HgCdTe or mercury Cadmium Telluride (also cadmium mercury telluride, MCT or CMT) is an Alloy of

The high dielectric constant of PbS leads to relatively slow detectors (compared to silicon, germanium, InSb or HgCdTe). Silicon (ˈsɪlɪkən or /ˈsɪlɪkɒn/ silicium is the Chemical element that has the symbol Si and Atomic number 14 Germanium (dʒɚˈmeɪniəm is a Chemical element with the symbol Ge and Atomic number 32

PbS can be formed as nanocrystals. A quantum dot is a Semiconductor whose Excitons are confined in all three Spatial dimensions.

Astronomy

Elevations above 2. 6 km (1. The kilometre ( American spelling: kilometer) symbol km is a unit of Length in the Metric system, equal to one thousand 63 mi) on the planet Venus are coated with a shiny substance. A mile is a unit of Length, usually used to measure Distance, in a number of different systems including Imperial units United States A planet, as defined by the International Astronomical Union (IAU is a celestial body Orbiting a Star or stellar remnant that is The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University 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. "Snowfall" redirects here For other uses see Snow (disambiguation or Snowfall (disambiguation. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 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. Bismuthinite is a mineral consisting of Bismuth Sulfide ( Bi 2 S 3 Tellurium (tɪˈlʊəriəm/ /tɛl- is a Chemical element that has the symbol Te and Atomic number 52 [1]

See also

References

External links

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