Antimony

Based on Wikipedia: Antimony

The Element That Could Reshape Global Supply Chains

In December 2024, China banned exports of certain critical minerals. Among them was antimony—an element most people have never heard of, yet one that touches nearly every aspect of modern technology and defense. Without antimony, your phone's flame-retardant casing wouldn't exist. Neither would the lead-acid battery in your car, the semiconductors powering your computer, or much of the ammunition stockpiled by militaries worldwide.

This is the story of a strange, ancient element that has traveled from Egyptian cosmetics to the frontlines of geopolitical conflict.

What Exactly Is Antimony?

Antimony sits at number 51 on the periodic table, represented by the curious symbol "Sb"—not derived from its English name, but from the Latin word stibium. It's a silvery-gray material that looks like a metal but behaves oddly. Scientists call it a "metalloid," meaning it shares characteristics with both metals and non-metals. Think of it as an element with an identity crisis—hard enough to scratch, yet so brittle that a sharp blow can shatter it.

At room temperature, antimony simply sits there, stable and unreactive. But heat it up, and it transforms, combining eagerly with oxygen to form antimony trioxide. This compound, as we'll see, is central to why antimony matters so much today.

The element belongs to group 15 of the periodic table, alongside nitrogen, phosphorus, and arsenic. Chemists call these elements "pnictogens"—a term derived from the Greek word for "choking," since many compounds in this family are toxic or suffocating gases. Antimony is no exception to the family's dangerous reputation.

A Material of Many Faces

One of antimony's stranger properties is that it exists in multiple forms, called allotropes. The version we typically encounter is a silvery, crystalline solid that forms in layered sheets. Imagine a stack of crinkled hexagonal honeycombs, with each layer only weakly bonded to those above and below. This structure explains why antimony is simultaneously dense—nearly seven times heavier than water—and surprisingly fragile.

But there's also a yellow form, created by cooling antimony hydrogen gas at extremely low temperatures, around negative 90 degrees Celsius. Expose this yellow antimony to light or warmth, and it rapidly transforms into a black powder.

Most dramatic is the so-called "explosive antimony." This variant forms during certain industrial processes and contains trapped chlorine atoms. Scratch it with a sharp tool, and you'll trigger an exothermic reaction—heat bursts forth, white fumes billow, and the material rapidly converts to ordinary metallic antimony. Grind it in a mortar, and it detonates. Scientists debate whether this truly qualifies as a separate form of antimony or simply antimony contaminated with reactive impurities.

Ancient Eye Shadow, Modern Industry

Humans have been using antimony compounds for at least five thousand years. The ancient Egyptians discovered that antimony sulfide—a dark, metallic material—made excellent kohl, the distinctive black eye makeup still worn across the Middle East and North Africa today. Archaeological evidence suggests this practice began around 3100 BCE, roughly the same time the Egyptians invented the cosmetic palette.

The name "kohl" itself comes from Arabic, and the substance was prized not just for beauty but for believed medicinal properties. The Roman naturalist Pliny the Elder, writing around 77 CE, described multiple methods for preparing antimony sulfide as medicine. He even distinguished between "male" and "female" forms—the male being the sulfide compound, while the superior female form was likely native metallic antimony, heavier and more durable.

But could ancient metalworkers actually work with pure antimony metal? The evidence is tantalizing but uncertain. An artifact described as part of a vase, allegedly made from antimony around 3000 BCE, was discovered in what is now Iraq. Scholars have puzzled over this find for over a century. Modern antimony is extremely brittle—far too fragile to shape into a useful vessel. Did ancient craftspeople know some lost technique for making it malleable?

Probably not. Later analysis suggested the object might have been carved from naturally occurring antimony metal found in the Caucasus region, where such deposits exist. And the "vase" itself might simply be a small ornament, misidentified by hopeful archaeologists. The mystery remains unsolved.

The Alchemists' Metal

Medieval alchemists were fascinated by antimony. It appears repeatedly in their manuscripts, including the influential Summa Perfectionis attributed to the mysterious Pseudo-Geber around the 14th century. These early chemists saw antimony as a purifying agent, capable of refining gold and separating precious metals from base ones.

The first clear description of isolating pure metallic antimony appeared in 1540, in Vannoccio Biringuccio's book De la Pirotechnia—a foundational text on metallurgy and pyrotechnics. This predates the more famous 1556 work by Georgius Agricola, who is sometimes incorrectly credited with discovering antimony.

A particularly colorful episode in antimony's history involves the book Currus Triumphalis Antimonii—"The Triumphal Chariot of Antimony"—published in Germany in 1604. The text claimed to be written by a 15th-century Benedictine monk named Basilius Valentinus, which would make it the earliest description of antimony preparation. Scholars now know this was a forgery; the actual author remains unknown, but the attribution to an ancient monk gave the work an aura of mystical authority.

There's even a folk etymology connecting antimony to dead monks. The word "antimony" supposedly derives from "anti-monachos"—Greek for "monk-killer"—because many early alchemists were monks, and antimony compounds are indeed poisonous. This explanation is almost certainly false, but it captures something true about the element's dangerous reputation.

Where Antimony Comes From

Antimony is rare. The Earth's crust contains only about 0.2 parts per million—roughly comparable to silver, making it the 63rd most abundant element. Despite this scarcity, antimony turns up in over a hundred different mineral species. Most commercial antimony comes from stibnite, a dark gray mineral with the chemical formula Sb₂S₃—the same substance the Egyptians used for kohl.

Extracting antimony from stibnite involves heating. Lower-quality ores are first concentrated using froth flotation, a process where air bubbles selectively carry certain minerals to the surface of a liquid. Higher-quality ores are heated to between 500 and 600 degrees Celsius, at which point the stibnite melts and separates from surrounding rock.

The purification continues through roasting, which converts the sulfide to an oxide. This antimony trioxide can then be reduced to pure metal using carbon at high temperatures in a process called carbothermal reduction. The details vary depending on ore quality—lower grades go to blast furnaces, while premium ores are processed in reverberatory furnaces.

China's Chokehold

Here's where antimony becomes a geopolitical flashpoint. In 2022, China produced 54.5% of the world's antimony supply. Russia contributed 18.2%, and Tajikistan added 15.5%. For regions like Europe and the United States, which must import virtually all their antimony, this concentration of supply represents a serious vulnerability.

The situation is getting worse, not better. Chinese production has actually been declining as the government closes mines and smelters under tightening environmental regulations. A major environmental protection law took effect in January 2015, and subsequent pollution standards have made economically viable production increasingly difficult. No significant new antimony deposits in China have been developed in roughly a decade, and existing reserves are being rapidly depleted.

Myanmar, another potential source, faces supply disruptions due to political instability. Meanwhile, the largest single antimony mine in the world—Xikuangshan in China's Hunan province—continues operating, but its output cannot grow indefinitely.

Then came December 2024, when China announced export bans on critical minerals including antimony. For industries dependent on this element, the implications are profound.

Why Antimony Matters Now

So what actually requires antimony? The applications are surprisingly diverse.

The most common use is in alloys—mixtures of metals. When you add small amounts of antimony to lead, the resulting alloy becomes harder and more rigid. This is crucial for lead-acid batteries, the kind that starts your car every morning. The lead plates inside these batteries need antimony to maintain their structure through thousands of charging cycles.

Antimony also improves solders—the metal mixtures used to connect electronic components. It strengthens bullets and ammunition. It makes plain bearings—the simple cylindrical bearings found in countless machines—more durable.

But perhaps antimony's most important modern application is fire resistance. Antimony trioxide, when combined with halogen-containing compounds, creates remarkably effective flame retardants. These chemicals don't extinguish fires exactly; rather, they interfere with combustion at the chemical level, slowing the spread of flames and reducing the release of heat. Nearly every electronic device contains plastics treated with these antimony-based flame retardants.

In the semiconductor industry, antimony serves as a "dopant"—an intentional impurity added to silicon or other materials to modify their electrical properties. Without precise doping, the transistors that power modern computers simply wouldn't work.

The Chemistry of Antimony

Chemists organize antimony compounds by their oxidation state—essentially, how many electrons the antimony atom has given up or accepted. Antimony primarily exists in two states: plus three (written as Sb(III)) and plus five (Sb(V)). The plus five state is more common in modern applications.

Antimony trioxide, formed when antimony burns in air, is one of the most industrially important compounds. In gaseous form, it exists as discrete molecules containing four antimony atoms and six oxygen atoms. But cool it down, and these molecules link together into extended polymer chains.

Antimony forms compounds with nearly every halogen—fluorine, chlorine, bromine, and iodine. The trifluoride version is particularly useful because it readily accepts additional fluorine atoms, forming complex ions that serve as catalysts in industrial chemistry. Antimony pentafluoride is one of the strongest Lewis acids known—a substance that eagerly accepts electron pairs from other molecules. Combined with hydrogen fluoride, it forms fluoroantimonic acid, considered the strongest superacid in existence, capable of dissolving glass and exploding on contact with water.

The Poisonous Element

Antimony's toxicity has been known for centuries. The element and its compounds can cause serious health problems, affecting the heart, lungs, and gastrointestinal system. Chronic exposure leads to a condition sometimes called "antimony spots"—skin eruptions that can persist for months.

The compound stibine—antimony combined with hydrogen—is particularly dangerous. It's thermodynamically unstable, meaning it wants to decompose, and at room temperature it does exactly that, breaking apart spontaneously. When it forms, usually as a byproduct of certain chemical reactions, it produces a toxic gas that can cause severe illness or death.

This toxicity likely contributed to the element's poor reputation among medieval scholars and the persistent folk beliefs about antimony killing monks. Whether or not the etymology is accurate, the danger is real.

Two Stable Forms, Dozens of Unstable Ones

Nature provides antimony in two stable isotopes—versions of the element with different numbers of neutrons in their nuclei. Antimony-121 makes up about 57% of naturally occurring antimony, while antimony-123 accounts for the remaining 43%. These proportions remain essentially constant wherever you find the element.

Scientists have created 37 additional radioactive isotopes in laboratories, with atomic masses ranging from 104 to 142. Most decay quickly—within seconds or minutes—but one, antimony-125, persists with a half-life of nearly three years. This isotope forms during nuclear fission and is one of the radioactive byproducts that must be carefully managed in nuclear waste.

The Name's Origins

Why "antimony"? The word's etymology remains genuinely uncertain, despite centuries of scholarly speculation.

The medieval Latin form was antimonium, which passed into modern European languages. One popular theory connects it to Greek words meaning "against aloneness"—allegedly because antimony is never found pure in nature, only combined with other elements. But this explanation has problems; ancient Greek would more naturally express such a concept using different word forms.

Another theory traces the word to Arabic sources. The German scholar Edmund Oscar von Lippmann suggested a hypothetical Greek word anthemonion, meaning "little flower," referring to the crystalline appearance of certain antimony compounds. Others point to ithmid, an Arabic term for antimony sulfide that appears in medieval medical texts.

The chemical symbol Sb, proposed by the Swedish chemist Jöns Jakob Berzelius in the early 19th century, comes from stibium, the Latin name used throughout antiquity. This word itself may derive from Greek stimmi, used by Attic playwrights in the 5th century BCE, which was possibly borrowed from Egyptian.

In ancient Egyptian, antimony was called mśdmt or stm—sounds that echo through Greek and Latin into the modern symbol on the periodic table.

An Experiment in Currency

In 1931, China's Guizhou province attempted something unusual: minting coins from antimony. The experiment failed almost immediately. Antimony coins proved too soft for circulation and—more seriously—toxic from regular handling. Production was quickly discontinued.

This brief monetary experiment highlights antimony's fundamental nature: useful in specific applications where its unique properties matter, but unsuitable as a general-purpose material. It's too brittle to shape easily, too soft to withstand wear, and too toxic for prolonged contact with skin.

Looking Forward

The antimony supply crisis is not a theoretical future problem—it's happening now. As China's production declines and export restrictions tighten, manufacturers worldwide are scrambling to secure alternative sources. Some companies are investigating recycling programs, extracting antimony from spent batteries and electronic waste. Others are exploring deposits in Australia, Canada, and other countries outside the current supply chain chokepoints.

But developing new mines takes years, even decades. Environmental regulations in Western countries make the permitting process lengthy. And antimony extraction, like most mining, carries genuine environmental costs—toxic runoff, habitat destruction, energy-intensive processing.

The irony is notable: antimony's most important application is making things flame-retardant, safer. Yet ensuring a stable supply of this safety-enhancing element has become one of the more precarious challenges facing global manufacturing.

For an element named, perhaps, for its tendency to never appear alone, antimony now stands at the center of questions about economic independence, supply chain security, and the hidden vulnerabilities of modern technology. The ancient Egyptians used it to beautify their eyes. Today, we rely on it to keep our electronics from catching fire and our cars starting on cold mornings. What was once kohl is now critical infrastructure.