![]() If a single atomic-weight value is needed, the Commission recommends using 207.2 ± 1.1, which corresponds to the common lead with a symmetric uncertainty covering normal materials. Assigning the aforementioned lead atomic weights as the lower and upper bounds of the interval, the standard atomic weight of lead is. The material is also from the Lewisian complex in north-western Scotland containing almost pure radiogenic 208Pb. The highest published lead atomic weight 207.9351 ± 0.0005 ( k = 2) is for monazite from a micro-inclusion. In a comprehensive review of several hundred publications and analyses of more than 8000 samples ( Zhu et al, 2021), published isotope data indicate that the lowest reported lead atomic weight of a normal terrestrial material is 206.1462 ± 0.0028 ( k = 2),ĭetermined for a growth of the phosphate mineral monazite from the Lewisian complex in north-western Scotland, which contains mostly 206Pb and almost no 204Pb. In the 1969 report, the Commission considered natural variations in the atomic weight of lead ranging from 207.184 to 207.293 and recommended the value of A r(Pb) = 207.2(1). However, the Commission's policy now aims for the implied range of the standard atomic weights to cover all normal sources of an element. Recognizing this, in 1961, the Commission recommended an atomic weight of 207.19 that was based on the chemical measurements, and stated that ".it quite well represented the lead most likely to be encountered in normal laboratory work". While elemental lead can serve as an abundant and homogeneous isotopic reference, deviations from the isotope ratios in other lead occurrences limit the accuracy with which a standard atomic weight can be given for lead. These variations in isotope ratios and atomic weights provide useful information in many areas of science, including geochronology, archaeology, environmental studies, and forensic science. The cost of pure lead may vary between $2 and $3 per 100 grams.The atomic weight of lead is quite variable in nature because the three heaviest isotopes are the stable end-products of the radioactive decay of uranium ( 238U to 206Pb and 235U to 207Pb)Īnd thorium ( 232Th to 208Pb). Pb can be combined with other metals to form a wide variety of pigments that are used in making paints, marking roads, and coating galvanized steel.Lead tape attached to golf clubs is known to modify the trajectory of the ball and manage swing defect.Nuclear reactors and X-ray machines with lead coverings help in blocking harmful X-rays and gamma-rays.There are other alloys of the metal as well used in printing plates, presses, and bearings. ![]() Solder joints comprising of lead and tin in equal amounts are used in joining pipes and electrical components.Pb crystal glasses are sometimes utilized as storage containers for corrosive liquids. Glasses coated with its oxide are used in making windows (known as leadlights) and roofing.It is used in pencils, flashings, lifting weights, anchors, and diving weight belts.Lead-sheathed cables and wires used in petrochemical plants function as good chemical barriers against hydrocarbons and moisture. ![]()
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