Difference between revisions of "Lead"
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| − | [[File:IMG 1265-0.JPG|thumb|220x220px|Weathered lead pieces with various lead oxides on the outer surface.[[File:IMG 1264.JPG|thumb|220x220px|The same lead pieces pictured earlier, re-melted to show fresh surfaces.]]]] | + | {{Infobox element |
| + | <!-- top --> | ||
| + | |image name=Lead_Ingot.JPG | ||
| + | |image alt= | ||
| + | |image size= | ||
| + | |image name comment=A freshly cast lead ingot | ||
| + | |image name 2= | ||
| + | |image alt 2= | ||
| + | |image size 2= | ||
| + | |image name 2 comment= | ||
| + | <!-- General properties --> | ||
| + | |name=Lead | ||
| + | |symbol=Pb | ||
| + | |pronounce= | ||
| + | |pronounce ref= | ||
| + | |pronounce comment= | ||
| + | |pronounce 2= | ||
| + | |alt name=Plumbum (Latin) | ||
| + | |alt names= | ||
| + | |allotropes= | ||
| + | |appearance= | ||
| + | <!-- Periodic table --> | ||
| + | |above=[[Tin|Sn]] | ||
| + | |below=[[Flerovium|Fl]] | ||
| + | |left=[[thallium]] | ||
| + | |right=[[bismuth]] | ||
| + | |number=82 | ||
| + | |atomic mass=207.2 | ||
| + | |atomic mass 2= | ||
| + | |atomic mass ref= | ||
| + | |atomic mass comment= | ||
| + | |series= | ||
| + | |series ref= | ||
| + | |series comment= | ||
| + | |series color= | ||
| + | |group=14 | ||
| + | |group ref= | ||
| + | |group comment= | ||
| + | |period=6 | ||
| + | |period ref= | ||
| + | |period comment= | ||
| + | |block=p | ||
| + | |block ref= | ||
| + | |block comment= | ||
| + | |electron configuration= [Xe] 4f<sup>14</sup> 5d<sup>10</sup> 6s<sup>2</sup> 6p<sup>2</sup> | ||
| + | |electron configuration ref= | ||
| + | |electron configuration comment= | ||
| + | |electrons per shell= | ||
| + | |electrons per shell ref= | ||
| + | |electrons per shell comment= | ||
| + | <!-- Physical properties --> | ||
| + | |physical properties comment= | ||
| + | |color= | ||
| + | |phase=solid | ||
| + | |phase ref= | ||
| + | |phase comment= | ||
| + | |melting point K= | ||
| + | |melting point C=327.46 | ||
| + | |melting point F= | ||
| + | |melting point ref= | ||
| + | |melting point comment= | ||
| + | |boiling point K= | ||
| + | |boiling point C=1749 | ||
| + | |boiling point F= | ||
| + | |boiling point ref= | ||
| + | |boiling point comment= | ||
| + | |sublimation point K= | ||
| + | |sublimation point C= | ||
| + | |sublimation point F= | ||
| + | |sublimation point ref= | ||
| + | |sublimation point comment= | ||
| + | |density gplstp= | ||
| + | |density gplstp ref= | ||
| + | |density gplstp comment= | ||
| + | |density gpcm3nrt=11.34 | ||
| + | |density gpcm3nrt ref= | ||
| + | |density gpcm3nrt comment= | ||
| + | |density gpcm3nrt 2= | ||
| + | |density gpcm3nrt 2 ref= | ||
| + | |density gpcm3nrt 2 comment= | ||
| + | |density gpcm3nrt 3= | ||
| + | |density gpcm3nrt 3 ref= | ||
| + | |density gpcm3nrt 3 comment= | ||
| + | |density gpcm3mp=10.66 | ||
| + | |density gpcm3mp ref= | ||
| + | |density gpcm3mp comment= | ||
| + | |density gpcm3bp= | ||
| + | |density gpcm3bp ref= | ||
| + | |density gpcm3bp comment= | ||
| + | |molar volume= | ||
| + | |molar volume unit = | ||
| + | |molar volume ref= | ||
| + | |molar volume comment= | ||
| + | |triple point K= | ||
| + | |triple point kPa= | ||
| + | |triple point ref= | ||
| + | |triple point comment= | ||
| + | |triple point K 2= | ||
| + | |triple point kPa 2= | ||
| + | |triple point 2 ref= | ||
| + | |triple point 2 comment= | ||
| + | |critical point K= | ||
| + | |critical point MPa= | ||
| + | |critical point ref= | ||
| + | |critical point comment= | ||
| + | |heat fusion=4.77 | ||
| + | |heat fusion ref= | ||
| + | |heat fusion comment= | ||
| + | |heat fusion 2= | ||
| + | |heat fusion 2 ref= | ||
| + | |heat fusion 2 comment= | ||
| + | |heat vaporization=179.5 | ||
| + | |heat vaporization ref= | ||
| + | |heat vaporization comment= | ||
| + | |heat capacity=26.650 | ||
| + | |heat capacity ref= | ||
| + | |heat capacity comment= | ||
| + | |heat capacity 2= | ||
| + | |heat capacity 2 ref= | ||
| + | |heat capacity 2 comment= | ||
| + | |vapor pressure 1=978 | ||
| + | |vapor pressure 10=1088 | ||
| + | |vapor pressure 100=1229 | ||
| + | |vapor pressure 1 k=1412 | ||
| + | |vapor pressure 10 k=1660 | ||
| + | |vapor pressure 100 k=2027 | ||
| + | |vapor pressure ref= | ||
| + | |vapor pressure comment= | ||
| + | |vapor pressure 1 2= | ||
| + | |vapor pressure 10 2= | ||
| + | |vapor pressure 100 2= | ||
| + | |vapor pressure 1 k 2= | ||
| + | |vapor pressure 10 k 2= | ||
| + | |vapor pressure 100 k 2= | ||
| + | |vapor pressure 2 ref= | ||
| + | |vapor pressure 2 comment= | ||
| + | <!-- Atomic properties --> | ||
| + | |atomic properties comment= | ||
| + | |oxidation states=4, 3, 2, 1 | ||
| + | |oxidation states ref= | ||
| + | |oxidation states comment=(2 and 4 are most common) | ||
| + | |electronegativity=1.87 | ||
| + | |electronegativity ref= | ||
| + | |electronegativity comment= | ||
| + | |ionization energy 1=715.6 | ||
| + | |ionization energy 1 ref= | ||
| + | |ionization energy 1 comment= | ||
| + | |ionization energy 2=1450.5 | ||
| + | |ionization energy 2 ref= | ||
| + | |ionization energy 2 comment= | ||
| + | |ionization energy 3=3081.5 | ||
| + | |ionization energy 3 ref= | ||
| + | |ionization energy 3 comment= | ||
| + | |number of ionization energies= | ||
| + | |ionization energy ref= | ||
| + | |ionization energy comment= | ||
| + | |atomic radius= | ||
| + | |atomic radius ref= | ||
| + | |atomic radius comment= | ||
| + | |atomic radius calculated= | ||
| + | |atomic radius calculated ref= | ||
| + | |atomic radius calculated comment= | ||
| + | |covalent radius= | ||
| + | |covalent radius ref= | ||
| + | |covalent radius comment= | ||
| + | |Van der Waals radius= | ||
| + | |Van der Waals radius ref= | ||
| + | |Van der Waals radius comment= | ||
| + | <!-- Miscellanea --> | ||
| + | |crystal structure= | ||
| + | |crystal structure prefix= | ||
| + | |crystal structure ref= | ||
| + | |crystal structure comment= | ||
| + | |crystal structure 2= | ||
| + | |crystal structure 2 prefix= | ||
| + | |crystal structure 2 ref= | ||
| + | |crystal structure 2 comment= | ||
| + | |speed of sound= | ||
| + | |speed of sound ref= | ||
| + | |speed of sound comment= | ||
| + | |speed of sound rod at 20= | ||
| + | |speed of sound rod at 20 ref= | ||
| + | |speed of sound rod at 20 comment= | ||
| + | |speed of sound rod at r.t.= | ||
| + | |speed of sound rod at r.t. ref= | ||
| + | |speed of sound rod at r.t. comment= | ||
| + | |thermal expansion= | ||
| + | |thermal expansion ref= | ||
| + | |thermal expansion comment= | ||
| + | |thermal expansion at 25= | ||
| + | |thermal expansion at 25 ref= | ||
| + | |thermal expansion at 25 comment= | ||
| + | |thermal conductivity= | ||
| + | |thermal conductivity ref= | ||
| + | |thermal conductivity comment= | ||
| + | |thermal conductivity 2= | ||
| + | |thermal conductivity 2 ref= | ||
| + | |thermal conductivity 2 comment= | ||
| + | |thermal diffusivity= | ||
| + | |thermal diffusivity ref= | ||
| + | |thermal diffusivity comment= | ||
| + | |electrical resistivity= | ||
| + | |electrical resistivity unit prefix= | ||
| + | |electrical resistivity ref= | ||
| + | |electrical resistivity comment= | ||
| + | |electrical resistivity at 0= | ||
| + | |electrical resistivity at 0 ref= | ||
| + | |electrical resistivity at 0 comment= | ||
| + | |electrical resistivity at 20= | ||
| + | |electrical resistivity at 20 ref= | ||
| + | |electrical resistivity at 20 comment= | ||
| + | |band gap= | ||
| + | |band gap ref= | ||
| + | |band gap comment= | ||
| + | |Curie point K= | ||
| + | |Curie point ref= | ||
| + | |Curie point comment= | ||
| + | |magnetic ordering= | ||
| + | |magnetic ordering ref= | ||
| + | |magnetic ordering comment= | ||
| + | |tensile strength= | ||
| + | |tensile strength ref= | ||
| + | |tensile strength comment= | ||
| + | |Young's modulus= | ||
| + | |Young's modulus ref= | ||
| + | |Young's modulus comment= | ||
| + | |Shear modulus= | ||
| + | |Shear modulus ref= | ||
| + | |Shear modulus comment= | ||
| + | |Bulk modulus= | ||
| + | |Bulk modulus ref= | ||
| + | |Bulk modulus comment= | ||
| + | |Poisson ratio= | ||
| + | |Poisson ratio ref= | ||
| + | |Poisson ratio comment= | ||
| + | |Mohs hardness= | ||
| + | |Mohs hardness ref= | ||
| + | |Mohs hardness comment= | ||
| + | |Mohs hardness 2= | ||
| + | |Mohs hardness 2 ref= | ||
| + | |Mohs hardness 2 comment= | ||
| + | |Vickers hardness= | ||
| + | |Vickers hardness ref= | ||
| + | |Vickers hardness comment= | ||
| + | |Brinell hardness= | ||
| + | |Brinell hardness ref= | ||
| + | |Brinell hardness comment= | ||
| + | |CAS number= | ||
| + | |CAS number ref= | ||
| + | |CAS number comment= | ||
| + | <!-- History --> | ||
| + | |naming= | ||
| + | |predicted by= | ||
| + | |prediction date ref= | ||
| + | |prediction date= | ||
| + | |discovered by= | ||
| + | |discovery date ref= | ||
| + | |discovery date= | ||
| + | |first isolation by= | ||
| + | |first isolation date ref= | ||
| + | |first isolation date= | ||
| + | |discovery and first isolation by= | ||
| + | |named by= | ||
| + | |named date ref= | ||
| + | |named date= | ||
| + | |history comment label= | ||
| + | |history comment= | ||
| + | <!-- Isotopes --> | ||
| + | |isotopes= | ||
| + | |isotopes comment= | ||
| + | |engvar= | ||
| + | }}[[File:IMG 1265-0.JPG|thumb|220x220px|Weathered lead pieces with various lead oxides on the outer surface.[[File:IMG 1264.JPG|thumb|220x220px|The same lead pieces pictured earlier, re-melted to show fresh surfaces.]]]] | ||
'''Lead''' is a chemical element with symbol Pb and atomic number 82. It is a very heavy and dense metal, and is well-known for its toxicity. | '''Lead''' is a chemical element with symbol Pb and atomic number 82. It is a very heavy and dense metal, and is well-known for its toxicity. | ||
==Properties== | ==Properties== | ||
===Chemical=== | ===Chemical=== | ||
| − | Lead is resistant to certain acids such as [[sulfuric acid]] but will react with [[nitric acid]] to form [[lead nitrate]], one of very few water-soluble lead compounds. Hot [[hydrochloric acid]] can also be used to convert lead into the poorly soluble [[lead(II) chloride]]. | + | Lead is resistant to certain acids such as [[sulfuric acid]] but will react with hot [[nitric acid]] to form [[lead(II) nitrate]], one of very few water-soluble lead compounds. Hot [[hydrochloric acid]] can also be used to convert lead into the poorly soluble [[lead(II) chloride]]. It will react very quickly with [[peracetic acid]] to form soluble [[lead(II) acetate]] and insoluble basic lead acetates. Lead will react with [[chlorine]] gas at elevated temperatures to produce the oily yellow liquid [[lead(IV) chloride]]. |
Freshly cut lead will oxidize in air. Lead compounds span a wide range of colors, and the pigments [[lead carbonate|white lead]], [[Lead(II,IV) oxide|red lead]], and [[Lead Chromate|chrome yellow]] are all derived from it. Solutions can be tested for lead by adding a few drops of [[potassium iodide]] solution, which forms a bright yellow precipitate of [[lead(II) iodide]]. [[Sodium sulfide]] can also be used, precipitating black [[lead sulfide]]. | Freshly cut lead will oxidize in air. Lead compounds span a wide range of colors, and the pigments [[lead carbonate|white lead]], [[Lead(II,IV) oxide|red lead]], and [[Lead Chromate|chrome yellow]] are all derived from it. Solutions can be tested for lead by adding a few drops of [[potassium iodide]] solution, which forms a bright yellow precipitate of [[lead(II) iodide]]. [[Sodium sulfide]] can also be used, precipitating black [[lead sulfide]]. | ||
===Physical=== | ===Physical=== | ||
| − | Lead is a soft | + | Lead is a soft, malleable, and dense post-transition metal. Metallic lead has a bluish-silver color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed to air. Lead has one of the lowest thermal and electrical conductivity of all metals. It is usually quickly identified from its high density and rather low melting point at 327 degrees Celsius. |
==Availability== | ==Availability== | ||
| − | Lead is available for sale as bars or ingots, in various purities. Certain wheels weights are made of lead or lead alloy (those of purer lead are very soft). Car batteries contain lead and lead oxide. Many items made in the earlier 20th century are a good source of lead, either pure or as alloy: old water pipes are a good bulk source; some car battery cable contacts were made of lead; very old hard drives tend to have counterweights made of lead; solders contain lead-tin alloy; scuba diving weight belts. The standard firearm bullets and shotgun pellets are also made of lead. Finally, lead fishing weights are widely available in outdoor or department stores. | + | Lead is available for sale as bars or ingots, in various purities. Oftentimes it is alloyed with antimony for hardness. Dissolving this alloyed lead in nitric acid will remove the antimony, as it precipitates as white [[antimony(III) oxide]] while the lead goes into solution. Certain wheels weights are made of lead or lead alloy (those of purer lead are very soft). Car batteries contain lead and lead oxide. Many items made in the earlier 20th century are a good source of lead, either pure or as alloy: old water pipes are a good bulk source; some car battery cable contacts were made of lead; very old hard drives tend to have counterweights made of lead; solders contain lead-tin alloy; scuba diving weight belts. The standard firearm bullets and shotgun pellets are also made of lead. Finally, lead fishing weights are widely available in outdoor or department stores. |
==Preparation== | ==Preparation== | ||
| Line 23: | Line 294: | ||
*Lead electrodes | *Lead electrodes | ||
*Lead battery | *Lead battery | ||
| + | *Lead casting | ||
==Handling== | ==Handling== | ||
===Safety=== | ===Safety=== | ||
| − | While lead is resistant to chemical attacks, it will rapidly oxidize into compounds that are extremely toxic to living beings. Lead poisoning is one of the most studied form of heavy metal poisoning in medicine and the nasty effects are well understood. | + | While lead is resistant to chemical attacks, it will rapidly oxidize into compounds that are extremely toxic to living beings. Lead poisoning is one of the most studied form of heavy metal poisoning in medicine and the nasty effects are well understood. It is not absolutely necessary to wear gloves while handling pieces of the metal, as long as hands are washed thoroughly after handling it. Lead in the metallic form is not absorbed through the skin at all. Soluble lead compounds, however, require more protection, and organolead compounds are the most dangerous as they are far more bioavailable and easily absorbed than any other source of lead. Because of its low melting point, lead is sometimes a popular use in home casting, although this has become less popular due to its toxicity. Contrary to popular belief, lead does not fume much when it is melted. At the temperatures that lead melts at, its vapor pressure is highly insignificant. Because of this, it is not necessary to wear a respirator while melting lead, though it is very necessary when working with lead dust, as this can be inhaled and absorbed through the lungs. It is not recommended to heat lead much higher than its melting point, as this may cause it to fume. |
Most lead compounds are poorly soluble in water, but [[lead(II) acetate]] and [[lead(II) nitrate]] are quite soluble and therefore are very toxic. | Most lead compounds are poorly soluble in water, but [[lead(II) acetate]] and [[lead(II) nitrate]] are quite soluble and therefore are very toxic. | ||
===Storage=== | ===Storage=== | ||
| − | Since it does not form volatile compounds under standard conditions, it's not necessary to be stored in special containers. | + | Since it does not form volatile compounds under standard conditions, it's not necessary to be stored in special containers. To prevent it from oxidizing, lead may be stored in a closed bottle under inert atmosphere, [[carbon dioxide]] is best. It's recommended to avoid storing it underwater or in any other liquids, as it will slowly oxidize, since there is some oxygen dissolved in liquid, and some lead oxide may flake off and contaminate the liquid. |
===Disposal=== | ===Disposal=== | ||
| − | Lead scraps can be taken to metal recycling facilities. Lead compounds should be converted to insoluble forms, before being taken to a hazardous waste facility. | + | Lead scraps can be taken to metal recycling facilities. Scraps of metal can also be collected and re-cast into fresh pieces. Lead compounds should be converted to insoluble forms, before being taken to a hazardous waste facility. |
==References== | ==References== | ||
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[[Category:Metals]] | [[Category:Metals]] | ||
[[Category:Elements]] | [[Category:Elements]] | ||
| − | |||
Revision as of 15:55, 5 August 2015
 A freshly cast lead ingot | |||||
| General properties | |||||
|---|---|---|---|---|---|
| Name, symbol | Lead, Pb | ||||
| Alternative name | Plumbum (Latin) | ||||
| Lead in the periodic table | |||||
| |||||
| Atomic number | 82 | ||||
| Standard atomic weight (Ar) | 207.2 | ||||
| Group, block | , p-block | ||||
| Period | period 6 | ||||
| Electron configuration | [Xe] 4f14 5d10 6s2 6p2 | ||||
| Physical properties | |||||
| Phase | solid | ||||
| Density near r.t. | 11.34 g/cm3 | ||||
| when liquid, at | 10.66 g/cm3 | ||||
| Heat of fusion | 4.77 kJ/mol | ||||
| Heat of | 179.5 kJ/mol | ||||
| Molar heat capacity | 26.650 J/(mol·K) | ||||
| pressure | |||||
| Atomic properties | |||||
| Oxidation states | 4, 3, 2, 1 (2 and 4 are most common) | ||||
| Electronegativity | Pauling scale: 1.87 | ||||
| energies |
1st: 715.6 kJ/mol 2nd: 1450.5 kJ/mol 3rd: 3081.5 kJ/mol | ||||
Lead is a chemical element with symbol Pb and atomic number 82. It is a very heavy and dense metal, and is well-known for its toxicity.
Contents
Properties
Chemical
Lead is resistant to certain acids such as sulfuric acid but will react with hot nitric acid to form lead(II) nitrate, one of very few water-soluble lead compounds. Hot hydrochloric acid can also be used to convert lead into the poorly soluble lead(II) chloride. It will react very quickly with peracetic acid to form soluble lead(II) acetate and insoluble basic lead acetates. Lead will react with chlorine gas at elevated temperatures to produce the oily yellow liquid lead(IV) chloride.
Freshly cut lead will oxidize in air. Lead compounds span a wide range of colors, and the pigments white lead, red lead, and chrome yellow are all derived from it. Solutions can be tested for lead by adding a few drops of potassium iodide solution, which forms a bright yellow precipitate of lead(II) iodide. Sodium sulfide can also be used, precipitating black lead sulfide.
Physical
Lead is a soft, malleable, and dense post-transition metal. Metallic lead has a bluish-silver color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed to air. Lead has one of the lowest thermal and electrical conductivity of all metals. It is usually quickly identified from its high density and rather low melting point at 327 degrees Celsius.
Availability
Lead is available for sale as bars or ingots, in various purities. Oftentimes it is alloyed with antimony for hardness. Dissolving this alloyed lead in nitric acid will remove the antimony, as it precipitates as white antimony(III) oxide while the lead goes into solution. Certain wheels weights are made of lead or lead alloy (those of purer lead are very soft). Car batteries contain lead and lead oxide. Many items made in the earlier 20th century are a good source of lead, either pure or as alloy: old water pipes are a good bulk source; some car battery cable contacts were made of lead; very old hard drives tend to have counterweights made of lead; solders contain lead-tin alloy; scuba diving weight belts. The standard firearm bullets and shotgun pellets are also made of lead. Finally, lead fishing weights are widely available in outdoor or department stores.
Preparation
Lead can be prepared by reducing one of its oxides with lead sulfide or from ions via electrowinning.
Projects
- Lead acetate
- Lead dioxide synthesis
- Lead tetroxide synthesis
- Lead electrodes
- Lead battery
- Lead casting
Handling
Safety
While lead is resistant to chemical attacks, it will rapidly oxidize into compounds that are extremely toxic to living beings. Lead poisoning is one of the most studied form of heavy metal poisoning in medicine and the nasty effects are well understood. It is not absolutely necessary to wear gloves while handling pieces of the metal, as long as hands are washed thoroughly after handling it. Lead in the metallic form is not absorbed through the skin at all. Soluble lead compounds, however, require more protection, and organolead compounds are the most dangerous as they are far more bioavailable and easily absorbed than any other source of lead. Because of its low melting point, lead is sometimes a popular use in home casting, although this has become less popular due to its toxicity. Contrary to popular belief, lead does not fume much when it is melted. At the temperatures that lead melts at, its vapor pressure is highly insignificant. Because of this, it is not necessary to wear a respirator while melting lead, though it is very necessary when working with lead dust, as this can be inhaled and absorbed through the lungs. It is not recommended to heat lead much higher than its melting point, as this may cause it to fume.
Most lead compounds are poorly soluble in water, but lead(II) acetate and lead(II) nitrate are quite soluble and therefore are very toxic.
Storage
Since it does not form volatile compounds under standard conditions, it's not necessary to be stored in special containers. To prevent it from oxidizing, lead may be stored in a closed bottle under inert atmosphere, carbon dioxide is best. It's recommended to avoid storing it underwater or in any other liquids, as it will slowly oxidize, since there is some oxygen dissolved in liquid, and some lead oxide may flake off and contaminate the liquid.
Disposal
Lead scraps can be taken to metal recycling facilities. Scraps of metal can also be collected and re-cast into fresh pieces. Lead compounds should be converted to insoluble forms, before being taken to a hazardous waste facility.
