LEAD

Name: Lead

Symbol: Pb

Group: 14

Period: 6

Block: p

Category: Post-transition metals

Atomic number: 82

Atomic mass: 207.2 u

Electrons per shell: 2, 8, 18, 32, 18, 4

Electronegativity: 2.33

Density: 11.34 g/cc

Melting point: 327.46ºC

Boiling point: 1749ºC

Thermal conductivity: 35 W (m·K)

Electrical conductivity: 4.8 × 10^6 S/m

Magnetic order: Diamagnetic

Ordinary state: Solid

Oxidation states: +2, +4

Hardness Mohs: 1.5

Vickers Hardness: No data

Brinell Hardness: 38.3 MPa

Most stable isotopes: Pb-204 (1.4%), Pb-206 (24.1%), Pb-207 (22.1%), and Pb-208 (52.4%)

Discoverer: Known since ancient times

Lead has been known since the dawn of Humanity.

It is one of the few elements that can appear native in the Earth's crust, but even its minerals, being so dense, stand out enough from the rest to be identified as ores of the element. This, and the fact that it is so easy to obtain, is why it has been used for at least more than five millennia B.C.

It never held any special regard, not even comparable to that of Copper (the least valued among all the "first" metals, except perhaps Tin). The reason is that it is too soft and, unlike those mentioned previously, it cannot be easily hardened (except with Antimony, Arsenic) and even when hardened, it remains a highly fragile element.

It was originally used in metallic form for applications of little or no mechanical responsibility, namely pipes, silverware, fountains, cutlery, as a monetary good, etc. The primordial uses of its compounds are associated with the coloring of ceramics, glass, as cosmetics...

It was obtained as a byproduct of Silver mining, a metal with which it is found associated in its ores, and vice versa (Silver is obtained from Lead mining and Lead from Silver mining). It is denser than silver but less dense than Mercury and Gold.

It is the element with the highest atomic weight whose atoms are still considered stable for all practical purposes (Bismuth is also considered "stable," but disintegrations have been detected in its nuclei; however, the amount of time required for such disintegration is so high that for all practical purposes, it is considered stable).

Lead is an atypical metal in many ways, unique.

Unlike most lighter elements (in terms of atomic weight), most of the Lead present in the Earth's crust comes from the disintegration processes of super-heavy elements such as Uranium, Thorium, Neptunium, and Plutonium (Actinides). Likewise, it is the preferred result in the disintegration processes of Radon, Cesium, Francium nuclei... virtually all (or most) ultra-heavy elements decay into Lead, Bismuth, or Mercury, and more rarely, into Thallium.

The Lead isotope Pb-208, with a combination of p=82 and n=126, is considered a "doubly magic" nucleus in nuclear physics and astrophysics due to the fact that both figures are among the select group of specific numbers that show a higher nucleon–nucleon binding index than what could, in principle, be calculated by the semi-empirical formula that calculates the binding energy between nucleons (protons and neutrons of the same nucleus). This makes Lead a more stable element than might be expected considering its enormous atomic weight, Z=82.

It is a chalcogen of the Carbon family with a valency of 4; in it, the most common oxidation states are +2 and +4, exactly the same as those of Platinum, although unlike other members of its own group (14 of the Periodic Table), in Lead, the most frequent oxidation state is +2, not +4 (although it is also stable).

The main mineral of this metal is Galena, a binary Sulfide of Lead and Sulfur with the composition PbS, where Lead represents more than 85% of the total mass of the compound, which explains its high density.

Galena at first glance resembles elemental Graphite, although it is denser. This has led to historical confusions and is the main reason why Graphite properly used for writing (or drawing) since ancient times is called "Lead" in English, a name that the element Lead in its pure state shares.

In German, it is called "Blei" (or "Bley") and has a Proto-Norse and/or Germanic origin.

The name we Spaniards give it, "Plomo", comes from the Latin "Plumbum". The name is important because other linguistic meanings derive from it, and it is widely used to refer to something dense.

The climbing plant known as "Plumbago" gets its name from Lead. The most accepted theory is that it is due to the bluish coloration of its flowers, while others argue that it was used medicinally to treat ailments related to the ingestion of the metal, which, being toxic, causes poisoning.

In Spain, the term "fontanero" is used for the worker specialized in pipes, bathrooms, sinks, fountains, domestic or higher-level hydraulic systems. In English, the worker of this trade is called a "Plumber", while in much of Latin America, they are called "Plomero". The origin of "Plumber" and "Plomero" is due to the fact that pipes were formerly (and increasingly less so) made of this metal.

Although the use of Lead to conduct large quantities of water was already employed before, it was Ancient and prosperous Rome that made it an intrinsic part of its culture. It was a vital element to supply all cities (urbes), large or small; it was the ideal element for the task: very resistant to corrosion, easy to work with, resistant to the passage of time, very durable, and recyclable.

Lead has been associated with Saturn since before the heyday of Alchemy in Europe and is the most "somber" metal of all for several reasons.

Its high density, attractive and robust luster, synonymous with everlasting strength, as well as the ease of engraving it (carving inscriptions or directly shapes or figures on metal plates) made it an excellent material to accompany gravestones.

When artillery replaced crossbows and bows and rendered plate armor obsolete (at the time, a well-trained man with this level of protection was practically immune to swords and could only be affected by hammer blows to the skull), Lead again came to the fore for a specifically lethal use: bullets and projectiles of all kinds, from the ancient Spanish arquebus balls to the modern long-range rifle bullets of Americans, Russians, and Germans.

Lead had great relevance during the Age of Alchemy, as it was considered the raw material for transmutation into Gold, being a metal similar to the king of metals. It was dense, soft, and unreactive. Alchemists saw Lead as "the oldest of metals," a kind of "grandfather" among the elements they knew. This is curious if we consider that, in any case, Lead is one of the youngest elements, precisely because producing it requires either a Supernova, which is the final phase of a massive star's life, or the disintegration of a super-heavy radioactive nucleus, such as those of the Actinides (the most known example being Uranium).

Something, however, that I must mention and that turns my stomach to think about, is that the Swede Niels Bohr, after many attempts, achieved through modern empirical science what was for centuries the goal of every alchemist worthy of the name: he transmuted Lead into Gold. For this, he subtracted 3 protons from Lead: Z=82 -3 = Z=79.

The problem, of course, is that the process itself is not profitable, but in any case, it is almost humorous to see how, in a way, those alchemists who were practically blind and did not have by far the tools or instruments that can be boasted today in some laboratories in countries like the United States, Russia, and some in the European Union, maintained more or less accurately that one of the possible ways to obtain gold was through the transmutation of Lead.

It is also no coincidence that the one who carried out the reaction (nuclear, not chemical) was Swedish: this nation has given birth to most of the great scientists related to chemistry and physics concerning metals since the late 18th century.

In its pure and uncorroded state, Lead exhibits a characteristic, unique bluish-gray color. It is an opaque metal, difficult to polish; even in the best of cases and with an elite grinder, it still maintains a "woody" appearance in the sense that a smooth and uniform surface is not achieved, even after sanding. This is taken to such an extreme that when we examine cooled Lead, we can notice differences in tone on its "skin". Few metals have this characteristic.

The initial bluish color is lost with relative ease through the formation of a protective oxide layer that, despite not being as resistant as those of highly reactive metals like Titanium and Chromium, occupies so much volume that it darkens the surface of the Lead and removes the bluish tint, turning it into an even more opaque gray. From this phase, Lead will hardly turn into any other color than an increasingly dark gray, bordering on a blackish tint.

It is a malleable metal, but not very ductile. Normally, ductile metals are malleable, but this maxim does not hold true in reverse. In other words, it is easier to obtain Lead sheets than wires of the pure metal. The addition of Tin and/or Indium improves the ductility of Lead, although very high percentages are needed to obtain wires (>50%), so we could hardly say that it is a Lead cable/wire or thread, as it would actually be an alloy.

Lead is not volatile even when pulverized and is very stable to impacts.

It has self-lubricating properties, and does not generate sparks through friction.

Its heat resistance is poor, and it is a poor conductor of heat and electricity.

Lead is poorly compatible with most metals that are not of its category (post-transition metals). It mixes well with Mercury, and moderately with Silver and Gold, but not with Copper and much less with other typical transition metals like Iron. The only exception is Zinc, with which it has a certain affinity.

The solubility of Lead in Copper is very low, unlike Tin, which is why it is used in conjunction with the latter to achieve "high-lead bronze" alloys in which a Lead-Tin alloy is prepared individually first and then added to molten Copper. It is the only exception in traditional Bronze, in which Tin can even be added as an ore.

Lead is toxic, although not as much as Mercury, Thallium, and Arsenic. Exposure to its vapors (Lead inhalation) results in the disease known as Saturnism. Fortunately, the Lead content in the body can be "saved" (excreted) with adequate medical treatments. Mercury, on the other hand, once it enters, does not leave.

Both are harmful, and both specifically attack the brain, altering its functions.

Mild Lead poisoning that does not reach levels high enough to trigger diseases can have permanent harmful effects such as an increase in violent behavior, increased aggressiveness, decreased social skills, and other traits that form part of the "perfect" picture (so to speak) for developing a criminal mind. In this sense, Lead again shows itself as a metal associated with negativity, in that projectiles, pesticides are made with it, and when it penetrates the brain, it can turn a healthy child into a future problematic boy or girl. This is why health authorities urge the civilian population to avoid all possible contact with the metal, although it should be clarified that actual poisoning is in no way as exaggeratedly easy to contract as has often been written. People read an alarmist news story and general panic breaks out. I would like you to keep in mind that until recently, water pipes were made of this metal; needless to say, handling it does not mean you are touching anthrax. In short, be careful, but do not panic due to paranoia.

Lead (Pb), chemical element with atomic number 82, is a post-transition metal of group 14, known for its high density (11.34 g/cm³) and relative abundance (~14 ppm in the Earth's crust). Among non-precious metals, like copper (Cu) or zinc (Zn), Lead stands out as the most chemically inert, classifying it as the least "base" and most "noble" of its category. Its low reactivity, combined with remarkable softness (Mohs hardness ~1.5) and a moderate melting point (327.5 °C), makes it ideal for applications where corrosion resistance is crucial, although its toxicity limits its use in contact with drinking water or food.

Lead is highly resistant to a wide range of corrosive environments. In dry and humid air, it forms a protective layer of lead oxide (PbO) that prevents further oxidation. It is stable in fresh and salt water, showing minimal solubility (~0.1 mg/L in pure water), although this slight dissolution releases lead ions (Pb²⁺) that, in the long term, can accumulate and pose a toxic risk, especially in drinking water systems. Lead resists alkalis, such as sodium hydroxide (NaOH), and a variety of organic solvents, including alcohols, ethers, and ketones with C-H-O bonds, which do not affect it. Its resistance to acids varies: it is notably resistant to sulfuric acid (H₂SO₄), both diluted and concentrated, due to the formation of a passivating layer of lead sulfate (PbSO₄), which is insoluble and protective, stopping further corrosion. It also resists hydrochloric acid (HCl), forming lead chloride (PbCl₂), although this layer is less effective. However, nitric acid (HNO₃) attacks Lead slowly, with a rate that increases with concentration, producing lead nitrate (Pb(NO₃)₂).

The resistance of Lead to sulfuric acid is its most outstanding characteristic, as this acid is one of the most corrosive in industrial and civil applications. This property allows Lead to be used in H₂SO₄ synthesis equipment, such as chambers and vessels, where its chemical inertia ensures durability. Even in a molten state, Lead is resistant to oxygen (O₂), surpassing tin (Sn) in chemical nobility, which makes it ideal for parts exposed to corrosive environments, such as pipes and linings in the chemical industry. However, its toxicity, linked to the release of Pb²⁺ ions, has led to restrictions on its use in applications such as drinking water pipes or food containers, where prolonged exposure can cause neurological and renal damage. In 2025, global Lead production (~4.5 million tons annually) is concentrated in batteries (lead-acid batteries) and shielding, but its handling requires strict precautions to avoid environmental and health contamination.

Lead (Pb), a chemical element with atomic number 82, is a post-transition metal of group 14 with a density of 11.34 g/cm³ and an abundance of ~14 ppm in the Earth's crust. Although it does not rival the versatility of metals like aluminum (Al) or iron (Fe) due to its low mechanical strength (Mohs hardness ~1.5) and toxicity, Lead is widely used for its high density, malleability, and remarkable corrosion resistance, especially against sulfuric acid (H₂SO₄). With a global production of ~4.5 million tons annually in 2025, Lead finds applications in diverse sectors, from energy to construction, although its use is increasingly restricted by environmental and health concerns.

One of the main uses of Lead is in lead-acid batteries, which account for ~80% of its global consumption. These batteries, used in vehicles, energy backup systems, and industrial applications, leverage Lead's ability to form durable electrodes and its resistance to H₂SO₄, which acts as an electrolyte. The formation of a passivating layer of lead sulfate (PbSO₄) during the charge-discharge cycle contributes to its longevity. In construction, Lead is used in linings and sheets for waterproofing, especially in roofs and drainage systems, due to its malleability and corrosion resistance in water and air. Historically, it was used in drinking water pipes, but this practice has been abandoned due to the release of Pb²⁺ ions, which cause neurological and renal damage.

In the chemical industry, Lead's inertia towards H₂SO₄ makes it ideal for manufacturing vessels and chambers in the synthesis of this acid, a critical process in the production of fertilizers and industrial chemicals. Its resistance to oxygen (O₂), even in a molten state (melting point 327.5 °C), also makes it useful in protective coatings for equipment exposed to corrosive environments. In shielding, Lead's high density makes it an essential material for protecting against ionizing radiation, such as in X-ray rooms, nuclear reactors, and containers for radioactive materials. To a lesser extent, Lead is used in alloys, such as printing metal (Pb-Sb-Sn) and solders, although these applications have decreased in favor of non-toxic alternatives.

Other uses include ammunition (bullets and shot), where its density and ease of molding are advantages, and pigments, such as white lead (2PbCO₃·Pb(OH)₂), although these have been replaced in many countries by safer compounds. The toxicity of Lead, which can accumulate in the body (biological half-life ~30 days), has led to strict regulations, such as the RoHS directive, which limits its use in electronics to less than 0.1% by weight. Despite these restrictions, Lead's versatility in industrial, energy, and radiation protection applications maintains its relevance as a material, provided it is handled with precautions to minimize its environmental and health impact.

In Antiquity, the uses of Lead were limited before Rome but expanded with its empire. In its pure or high-purity state, it was used in the manufacture of vessels, such as bowls and jars, and in plumbing for pipes, taking advantage of its ease of molding and resistance to fresh and salt water. Unlike copper (Cu), which develops a corrosive patina (basic copper carbonate, Cu₂(OH)₂CO₃) or sulfates that alter the taste of water, Lead maintained water quality without requiring frequent cleaning. Its low cost in Antiquity, compared to steel or bronze, made it ideal for water distribution networks and septic systems, many of which, like the Roman aqueducts, remain functional in some parts of the world. In alloys, Lead is not miscible with copper, so it was added to bronze (Cu-Sn) in small quantities after melting a mixture of Lead and Tin (Sn), improving the fluidity of the molten metal for complex molds, a practice that persists in certain modern processes, albeit with different applications.

The theory that Lead contributed to the fall of the Roman Empire (5th century A.C.) is based on its use in pipes and vessels, which could have released Pb²⁺ ions into drinking water, causing chronic poisoning. With a solubility of ~0.1 mg/L, Lead could accumulate in the body (biological half-life ~30 days), causing neurological and renal damage. Some historians have suggested that this exposure affected the health of the population, weakening Roman society, and have even speculated that emperors like Caligula or Nero, known for erratic behavior, suffered from Lead poisoning. However, this hypothesis is questionable. The Romans knew the toxicity of Lead and used noble metals like silver (Ag) or gold (Au, equivalent to >18 modern carats) for elite tableware, minimizing exposure in the upper classes. Furthermore, Lead consumption was not exclusive to Rome; other civilizations, such as the Germans or Gauls, also used potentially contaminated materials, without showing a comparable decline.

The fall of Rome is more attributable to complex factors: migrations of barbarian peoples (Germans, Vandals), internal conflicts due to the rise of Christianity, which challenged Roman military tradition (linked to the god Mars, origin of "martial"), and a corrupt government that relaxed citizenship requirements and weakened social cohesion. Lead poisoning, though real, was not a determining factor compared to these substantial socio-political and military dynamics. Modern Lead production (~4.5 million tons in 2025) focuses on batteries and shielding, but its use in contact with drinking water has been banned in many countries due to regulations such as RoHS, which limit its presence in products to 0.1% by weight. The legacy of Lead in Antiquity reflects its technological importance, but its impact on the fall of Rome has been exaggerated compared to more substantial historical causes.

Despite its toxicity and lower mechanical resistance compared to metals like aluminum (Al) or iron (Fe), Lead is widely used for its high density, corrosion resistance (especially to sulfuric acid, H₂SO₄), low melting point (327.5 °C), malleability (Mohs hardness ~1.5), and self-lubricating properties. With a global production of ~4.5 million tons annually in 2025, its applications range from energy to radiation protection, although regulations like RoHS limit its use in electronics (<0.1% by weight) due to environmental and health risks.

The high density of Lead makes it ideal for applications where weight is functional. In fishing, sinkers, manufactured by injecting molten Lead into molds with a hole for the line, are resistant to fresh and salt water, although they are being replaced by less toxic materials such as zamak (Zn-Al-Mg-Cu alloy) or coated steel. In ammunition, Lead is the preferred material for bullets and shot since its use in arquebuses in the 15th century, led by Spain under Gonzalo Fernández de Córdoba during the Italian Wars. Its density provides high kinetic energy, improving penetration, but its toxicity has prompted research into alternatives, such as steel with tungsten (W, ~20%) used in tank projectiles during World War II. The persistence of Lead in the environment after war conflicts has generated criticism, although focusing on replacing it without addressing the conflicts themselves is questionable. In ballistic protection, Lead is combined with materials like Kevlar in vests and anti-riot or anti-explosive suits, providing density to absorb impacts, although its weight limits mobility.

In radiological shielding, the high atomic weight of Lead (Z=82) makes it a key material for blocking ionizing radiation, such as gamma and X-rays. It is used in sheets for X-ray rooms in hospitals, containers for radioactive waste (e.g., uranium hexafluoride, UF₆), and protective suits in nuclear disasters like Chernobyl (1986) and Fukushima (2011). Compared to steel (Fe, Z=26), Lead is more effective due to its higher nuclear density, although steel-lead-steel structures reduce costs and weight. Lead must be replaced periodically, as it can absorb neutrons, transforming into unstable isotopes (e.g., Pb-204 + n → Pb-205 → Tl-205). In the chemical industry, its resistance to H₂SO₄ allows its use in vessels and chambers for the synthesis of this acid, as well as in coatings for structures exposed to corrosives. In lead-acid batteries, which dominate ~80% of its consumption, Lead forms durable electrodes, leveraging the passivating layer of PbSO₄.

In alloys, Lead is combined with tin (Sn) in solders (typically 60% Sn-40% Pb), valued for their low melting point and conductivity, although their use is decreasing due to environmental restrictions. Babbitt alloy (Pb-Sb-Sn) is used in bearings for its self-lubricating properties. In music, church organ pipes, made of a Pb-Sn alloy, take advantage of Lead's density to produce deep and resonant tones, contrasting with its wartime use. In optics, lead oxide (PbO) is added (~14–40%) to glasses like "lead crystal" (invented by George Ravenscroft in 1674), increasing refraction and brilliance for jewelry and decorations, such as Swarovski crystals. This glass, chemically inert once formed, does not pose significant risks, although its manufacture requires precautions. White lead (2PbCO₃·Pb(OH)₂), a historical pigment, and Lead stabilizers in plastics (PVC) for UV resistance are in decline due to their toxicity, being surpassed by alternatives like cadmium (Cd), although also problematic.

Lead (Pb), a chemical element with atomic number 82, is a post-transition metal of group 14 with a density of 11.34 g/cm³ and an abundance of ~14 ppm in the Earth's crust. Known since Antiquity for its malleability and corrosion resistance, Lead has played a significant role in alchemy, astrology, and the pseudoscientific traditions that preceded modern chemistry and astronomy. Its association with concepts of antiquity, transformation, and heaviness made it a powerful symbol in the folklore and worldview of various cultures, particularly in the Greco-Roman and alchemical contexts.

In alchemy, Lead was considered the "grandfather of metals," the oldest and "base" (least pure) material, in contrast to gold (Au), seen as the most noble and perfect form. Alchemists believed that all metals could be transformed by natural or artificial processes, and Lead, due to its density and certain chemical properties shared with gold (such as its relative stability), was the ideal starting point for transmutation into gold, the supreme goal of alchemy. This process not only sought material transformation but symbolized spiritual purification, reflecting the idea of elevating something "inferior" to a higher state. Alchemy also associated Lead with specific processes, such as fermentation or putrefaction (in Capricorn) in the "dry path" and "wet path", two sequences of transformation that linked metals to zodiac signs: Lead (Capricorn/Aquarius), Tin (Sagittarius/Pisces), Iron (Scorpio/Aries), Copper (Libra/Taurus), Mercury (Virgo/Gemini), Silver (Cancer), and Gold (Leo). Each sign represented an alchemical stage, such as calcination, dissolution, or sublimation, applicable to metals and organic compounds, symbolizing the refinement of matter and spirit.

In astrology, Lead is linked to the planet Saturn, which shares its symbol (♄) in alchemy and astrology, reflecting its connection with Cronos, the Greco-Roman god of time and father of Zeus (Jupiter). Saturn, perceived as slow, heavy, and ancient, contrasted with Jupiter, associated with tin (Sn) and vitality. Lead, therefore, symbolized ponderousness, maturity, and stability, but also melancholy and the weight of time. It is associated with the zodiac signs Capricorn and Aquarius, although the connection with Aquarius is less known in modern astrology, which often omits its relationship with Lead in favor of other metals such as zinc (Zn) or platinum (Pt). In alchemy, the signs not only represented celestial influences but also stages of transformation: for example, the "fermentation" of Capricorn could allude to controlled decomposition (putrefaction) or the creation of noble substances, such as wine from grapes, a parallel with the artistic transformation described by figures like Salvador Dalí or Shakespeare, who saw alchemy as a metaphor for the creation of beauty from humble raw materials.

The folkloric legacy of Lead transcends its material use, evoking ideas of transformation and duality: a "base" metal with the potential for the sublime. Although its modern production (~4.5 million tons annually in 2025) focuses on practical applications such as batteries and shielding, its symbolism in alchemy and astrology reflects an ancient vision of matter as a means for transcendence, from the heaviness of Lead to the purity of Gold, a metaphor that endures in culture and art.