Vapour pressure A measure of the propensity of a substance to evaporate. Pressure and temperature data — advanced. Listen to Lead Podcast Transcript :. You're listening to Chemistry in its element brought to you by Chemistry World , the magazine of the Royal Society of Chemistry.
Hello, this week we're sinking to new depths as we meet the metal that spawned the plumb line, a rock group, plumbing and even poisoning, not to mention a generation of alchemists who tried in vain to turn this substance into gold.
It is of course lead, and here to swing it for us is science writer Phil Ball. Lead is the Eeyore of metals - slow, dull and heavy. In its Latin form, plumbum , it enters our vocabulary by virtue of its soft and ponderous character: we once plumbed depths with a suspended grey blob of the stuff, emphatically commanded by gravity, while plumbers have long since traded their malleable lead pipes for plastic.
Everything associated with lead tends towards over-burdened gloom: in the ancient scheme of metal symbolism, lead was linked to Saturn, the melancholy planet, personified by the old god also called Cronos who castrated his father and swallowed his children. Even the spark of glamour the metal gets from association with the world's greatest rock band stems from the Eeyorish prediction that they would sink like a lead balloon or zeppelin.
Yes, lead is the original heavy metal, the most notorious offender in that toxic group. Lead damages the brain and the kidneys, it can cause anaemia and a form of gout with the doleful title of saturnine gout. Even the Romans knew about lead poisoning - the doctor Cornelius Celsus warned about the bad effects of lead white, used in paint and cosmetics, while the engineer Vitruvius recommended earthenware pipes over lead ones.
Yet we were slow to learn. Lead white, a form of lead carbonate, remained the artist's best white pigment right up until the nineteenth century, when it was replaced by zinc white. As paint manufacture became industrialized, lead white spread sickness and death among factory workers: a report in the Transactions of the Royal Society in the seventeenth century listed vertigo, dizziness, blindness, stupidity and paralytic affections among the conditions it caused.
And as late as in the toy manufacturer Mattel was forced to recall millions of toys made in China that had been coloured with lead paint. Meanwhile, a toxic trickle of lead from solder and the electrodes of batteries leaches slowly from landfill sites throughout the world. In the European Union effectively banned lead from most consumer electronics, but it remains in use elsewhere. To alchemists, lead was the lowliest of metals - in a sense, it was where all metals started.
In talk of base metals, which alchemy tried to turn to silver and gold, there was none so base as lead. The alchemists believed that lead slowly matured into other metals in the ground. But alchemy also offered lead a chance to shake off its grey and graceless image. It does not take much to draw splendid colours out of lead. The ancient technologists blanched the dull metal by placing lead strips in pots with vinegar, and shutting them away in a shed full of animal dung.
The vinegar fumes and gas from fermenting dung conspired to corrode lead into lead white. Heat this gently, and it turns yellow: a form of lead oxide known as litharge or, in the Middle Ages, massicot.
Heat it some more, and it goes bright red, as you form a different kind of oxide. Both of these substances were used by artists - red lead was, for a long time, their finest red, used for painting many a bright robe in the Middle Ages.
It was the signature colour of Saint Jerome. To the alchemists, those colour changes weren't just a way to make pigments. They signified some more profound alteration taking place in the metal, bringing it close to the colour of gold.
It's no wonder, then, that their experiments often began with lead. They came no closer to making real gold, but they started to explore the processes of chemical transformation. Lead, however, seems habituated to revealing its true and dirty colours. Exposed to air, it may go on taking up oxygen until it turns black.
Red lead has become chocolate brown on paintings throughout the world, from Japan to India to Switzerland. In urban galleries there is another danger, as the sulfurous fumes of pollution react with red lead to from black lead sulphide. There seems to be no getting away from it: lead has a glum and melancholy heart. Phil Ball plumbing the depths of the scientific story of lead. The next edition of Chemistry in its element promises to be a record breaker. You can learn a lot about someone by meeting their family and the same is true for the element.
That's how we come to know so much about astatine. Often trumpeted as the rarest naturally occurring element in the world, it's been estimated that the top kilometre of the earth's crust contains less than 50 mg of astatine making it Guinness world record's rarest element. And you can hear Mark Peplow telling the tale of the world's rarest chemical in next week's Chemistry in its element. I'm Chris Smith, thank you for listening, see you next time. Chemistry in its element is brought to you by the Royal Society of Chemistry and produced by thenakedscientists.
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Data W. Haynes, ed. Version 1. Coursey, D. Schwab, J. Tsai, and R. Dragoset, Atomic Weights and Isotopic Compositions version 4. Periodic Table of Videos , accessed December Podcasts Produced by The Naked Scientists. Download our free Periodic Table app for mobile phones and tablets. Explore all elements. D Dysprosium Dubnium Darmstadtium. E Europium Erbium Einsteinium. F Fluorine Francium Fermium Flerovium. G Gallium Germanium Gadolinium Gold.
I Iron Indium Iodine Iridium. K Krypton. O Oxygen Osmium Oganesson. U Uranium. V Vanadium. X Xenon. Y Yttrium Ytterbium. Z Zinc Zirconium. Membership Become a member Connect with others Supporting individuals Supporting organisations Manage my membership. Facebook Twitter LinkedIn Youtube. Discovery date. It played a crucial role during the Industrial Revolution. Lead's symbol Pb originates from its Latin name, plumbum — which actually used to refer to soft metals more generally.
In fact, lead and tin were not clearly distinguished until the sixteenth century, when lead was referred to as plumbum nigrum black lead and tin as plumbum candidum or album bright lead.
The Latin root name has persisted in other languages — for example it is 'plomb' in French — and in English through the words 'plumber' and 'plumbing', as lead was a popular material for pipes owing to its high corrosion resistance. Pure lead is bluish-white in colour with a bright lustre, and crystallizes in a face-centred-cubic structure, with no known allotropic modifications 2.
On exposure to moisture this lustre is lost through the formation of an oxide coating that protects the underlying metal. Lead is found in nature, rarely in pure form but in ores with other metals — the most abundant one in the Earth's crust being galena PbS.
Natural formation of lead occurs by radioactive decay of uranium and thorium through radon Rn. Four stable isotopes are known, Pb, Pb, Pb and Pb, the first three of which are used for estimating the ages of rocks. An early route to extract lead from ores pictured involved roasting an ore in air, which converts its lead sulfide to oxide and sulfate forms, and subsequently smelting those with limestone and coke to obtain crude lead.
Today about half of the annual production of lead comes from mining, and the rest from recycling. Lead compounds are associated with several significant discoveries crucial to modern technologies. Rectifying properties were discovered at metal—galena point contacts by F. Braun in 3. In J. Bose detected an electromagnetic wave using galena — a key event for the development of the radio 4. Infrared detectors based on lead chalcogenides that is, sulfides, selenides and tellurides represented a major advance in infrared technology, for example for night vision and for the spectroscopic analytical techniques that are now available to chemists.
Lead chalcogenides are also characterized by low direct-bandgaps, which change depending on the sizes of the crystallites and cover a broad spectral range — a phenomenon called the quantum confinement effect, which forms the basis for devices such as field-effect transistors, solar cells and photodetectors. The widespread production and consumption of lead continued until the twentieth century, through uses in petrol, lead-acid batteries, paint, radiation shielding and in the polyvinyl plastic industry as a stabilizer.
However, humans are susceptible to lead poisoning by either acute or, more often, chronic exposure. Lead accumulates in the body and interferes with various processes, resulting in neurotoxic effects with a variety of symptoms. Even as far back as the Roman period maladies were correlated with lead, through the use of 'lead sugar' lead acetate beverages and pipes for water supply.
It is this softness that makes it easy to squeeze or roll lead into different shapes. For winemakers in the Roman Empire, nothing but lead would do. When boiling crushed grapes, Roman vintners insisted on using lead pots or lead-lined copper kettles. From the Middle Ages on, people put lead acetate or " sugar of lead " into wine and other foods to make them sweeter. Lead touched many areas of Roman life.
It made up pipes and dishes, cosmetics and coins, and paints. Eventually, as a host of mysterious maladies became more common, some Romans began to suspect a connection between the metal and these illnesses. Julius Caesar , for example, managed to father only one child, even though he enjoyed women as much as he enjoyed wine.
His successor, Caesar Augustus , was reported to be completely sterile. Some scholars suggest that lead could have been the culprit for the condition of both men and a contributing factor to the fall of the Roman Empire. A form of lead intoxication known as saturnine gout takes its name from ancient Rome.
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