Lead Symbol: Pb Atomic Number: 82Atomic Weight: 207.2Element Group: Basic Metal Discovery: Known to the ancients, with a history dating back at least 7000 years. Name Origin: Anglo-Saxon: lead; symbol from Latin: plumbum.Lead is the only metal in which there is zero Thomson effect. Atomic Radius (pm): 175Atomic Volume (cc/mol): 18.3Covalent Radius (pm): 147Ionic Radius: 84 (+4e) 120 (+2e)Specific Heat (@20°C J/g mol): 0.159Fusion Heat (k J/mol): 4.77Evaporation Heat (k J/mol): 177.8Debye Temperature (°K): 88.00Pauling Negativity Number: 1.8First Ionizing Energy (k J/mol): 715.2Oxidation States: 4, 2Electronic Configuration: [Xe] 4f Pb (52.3%).
These dates are consistent with previously determined crystallization and emplacement ages of these samples using different radiogenic systems.
These high-precision ages allow refinement of the timing of some of the high-Ti basaltic volcanism on the Moon.
Crystallization ages of three different high-Ti basalt units, integrating these new Pb/Pb ages with previous Rb-Sr and Sm-Nd age determinations, are consistent with previous estimates but associated with uncertainties 3 to 5 times lower.
The Pb values in both sections are relatively smaller from 15.649 to 17.126 and 37.744–38.199 in the Weng’an section, and from 16.034 to 16.783 and 38.602–39.391 in the Xiuning section, respectively.
These data yielded two Pb isotope isochron ages of 536±39 and 572±36 Ma, respectively.
These ages well accord with other published data and we suggest that they represent the depositional ages for the Lower Cambrian Hetang Formation and the upper Neoproterozoic Doushantuo Formation in South China.
Density (g/cc): 11.35Melting Point (°K): 600.65Boiling Point (°K): 2013Properties: Lead is an extremely soft, highly malleable and ductile, poor electrical conductor, resistant to corrosion, blue-white shiny metal that tarnishes to dull gray in air.
In addition, the data obtained in this study confirm that tranquillityite contains very low amounts of initial common Pb and has a high-Pb ionization efficiency, making it an excellent candidate for Pb/Pb dating by ion microprobe.
The higher spatial resolution afforded by Nano SIMS 50 and the recent discovery of tranquillityite in several terrestrial mafic rocks opens up a new area of research allowing an independent and rapid age dating of basaltic rocks in polished sections.