Antimony is a chemical element with atomic number 51 in the periodic table. With an estimated 0.00002% to 0.0005% ppm natural abundance, antimony is the 62nd most plentiful substance found in Earth’s crust. Being a member of the nitrogen family of elements, this toxic metalloid has five valence electrons that take part in the formation of a chemical bond.
Known since ancient times, element 51 has been used as a medicine and in various cosmetic preparations. The black eyeliner (‘kohl’) popularly used as makeup by the last queen of the Ptolemaic Kingdom of Egypt, Cleopatra, is fashionable even today.
Chemical and Physical Properties of Antimony
|Color||A lustrous, silvery, bluish-white metalloid|
|Physical state||Solid at room temperature|
|Half-life||From less than 1.5 milliseconds to 2.75856 years|
|Melting point||630.628°C, 1167.13°F, 903.778 K|
|Boiling point||1587°C, 2889°F, 1860 K|
|Van der Waals radius||0.159 nm|
|Ionic radius||0.76 (+3) Å|
|Most characteristic isotope||121Sb|
|Electronic shell||[Kr] 4d10 5s2 5p3|
|The energy of the first ionization||834 kJ.mol-1|
|The energy of the second ionization||1595 kJ.mol-1|
|The energy of the third ionization||2443 kJ.mol-1|
|Covalent Radius||1.40 Å|
|Atomic Radius||1.53 Å|
|Atomic Volume||18.23 cm³/mol|
|Name Origin||Greek: anti and monos (not alone); mineral stibnite|
|Discoverer||Known to the ancients|
|Uses||Alloys, semiconductors, plastics, chemicals, cold remedies|
|Description||Silvery-white, brittle semi-metal|
With the chemical symbol Sb, atomic number 51, atomic mass of 121.75 g.mol-1, and electron configuration [Kr] 4d105s25p3, аntimony is a semi-metallic chemical element. It reaches its boiling point at 1587°C, 2889°F, 1860 K, while the melting point is achieved at 630.628°C, 1167.13°F, 903.778 K. This member of the nitrogen group of elements in the periodic table has an electronegativity of 1.9 according to Pauling, whereas the atomic radius according to van der Waals is 0.159 nm. The chemical properties of this chemical are similar to the elements lead, arsenic, and bismuth.
There are four allotropes of element 51:
- White Sb (explosive metastable form);
- Yellow Sb (metastable form);
- Black Sb (metastable form);
- A stable metallic form.
Antimony can exist in two aggregate states. While the antimony metal is a very brittle, silvery, moderately hard metal, the non-metallic form is a grey powder. The shell structure of element 51 is 220.127.116.11. The atomic structure of antimony is relatively stable in dry air, and this chalcophile is unreactive when exposed to dilute acids or alkalis. When exposed to newly formed hydrogen, antimony may form stibine (SbH3).
How Was Antimony Discovered?
People were powdering sulfide minerals containing antimony and have used it both as a medicine and in cosmetics ever since ancient times. They knew this substance under the Arabic name ‘kohl’, meaning ‘black powder’.
Women of Egypt, Arabia, Ancient Greece, as well as the Romans found it fashionable to underline the eyes with this black cosmetic preparation made of antimony sulfide. The antimony sulfide ore was first ground in a pestle and mortar, after which it was mixed with oils or animal fats. In this way, people of ancient Egypt were making kohl paint which they applied to the eyes using a thin piece of wood.
Ancient Egyptians and people of Arabia also held a belief that this black preparation has medicinal properties, as well as specific magical and religious qualities. By applying thick lines of kohl under the eyes, ancient people believed that it would protect the thin skin on the face from the sun, protect them from various diseases, and keep them safe from the Evil Eye.
Since the Protodynastic Period of Egypt (ca. 3100 BCE), stibnite, or black antimony sulfide, was administered to patients with fevers or skin conditions. Antimony as a medicine was also popular among the ancient physicians of Ancient Greece, Arabia, as well as with the Romans.
The ancient physician Dioscorides of Anazarba called this substance ‘stibi’ and used it as a medicine against ulcers, burns, and skin problems. He also observed that stibnite can melt like a lead when heated on coal. In this way, Dioscorides of Anazarba is the first person who has pointed out the antimony metal. The ancient physicians used this antimony allotrope as a hangover and overindulgence remedy, as well as to alleviate constipation.
The Contribution of Nicolas Lémery
In modern times, the French chemist Nicolas Lémery (1645 – 1715) is noted as the first scientist who has performed scientific experiments and studied the chemical properties of the element 51.
How Did Antimony Get Its Name?
The name of this chemical element originates from the Greek word ‘anti-monos‘, which means ‘not alone’, but it’s also etymologically related to the Medieval Latin word ‘antimonium’. Antimony got its name because it is almost always found combined with sulfur or with heavier metals such as copper, lead, and silver.
Antimony’s chemical symbol comes from its Latin word ‘stibium’. This historical name of element 51 is derived from the Greek word ‘stíbi’, meaning ‘eye paint’.
Where Can You Find Antimony?
Element 51 can be found in nature mostly combined with sulfur. Antimony typically occurs in the sulfide mineral stibnite (Sb2S3), tetrahedrite (a copper, iron, antimony sulfide mineral / (CuFe)12Sb4S13), as well as in valentinite (Sb2O3).
For commercial purposes, antimony is prepared in many forms: ingots, broken pieces, granules, cast cake, powder, shot, as well as single crystals. With approximately 84% of the world’s share, China is the largest antimony producer, followed by Africa, Bolivia, and Tajikistan.
List of Antimony Minerals
There are over a hundred minerals in which antimony can be found. The following is a list of antimony minerals in which this chemical element most often occurs:
- Samsonite (mineral)
Antimony in Everyday Life
Classified as a metalloid (or semimetal), antimony possesses both metallic and non-metallic properties. However, both the industrial and commercial uses of antimony are limited due to the high toxicity of this chemical. Its everyday use can be observed in the following instances:
- Antimony compounds have a wide application as paint pigments. Namely, antimony potassium tartrate (tartar emetic) is employed in the process of leather tanning, while the textile industries make use of it as a mordant, i.e. fixing agent that is required for dyeing leather and various types of fabrics;
- Kohl is even today widely popular and used as an eyeliner all around the Globe;
- When added to brass used for casting bells, antimony adds strength and hardness to the metal. Bullets, lead shots, and cable sheathing are also hardened by a few percent of antimony added to their respective compound;
- Antimony is used in the electronics industry to make some semiconductor devices, such as infrared detectors and diodes;
- The use of antimony is applied in the production of Babbitt metal (or bearing metal). The term ‘babbitt metal’ refers to any of the several tin- or lead-based alloys that are used as a bearing surface in a plain bearing. This antimony alloy quickly adapts its shape to the moving part. In that way, it lowers the friction between the surfaces and supports the equal spreading of lubricating oil between the metals;
- This semimetal is also used for manufacturing of the brake pad systems used for heavy vehicles;
- Antimony is applied as an alloy component of battery electrodes and of pewter, type metal (in printing presses), solder, storage batteries, cable sheathing, pipe metal, and castings;
- When added to polyester resins, antimony is used to manufacture light aircraft engine covers;
- The flame-retardant uniforms of firefighters contain antimony. Despite the health concerns, it has been confirmed that fire retardant clothing doesn’t raise antimony toxicity levels which leads to adverse health effects;
- Used as fire retardants, antimony compounds reduce the flammability of fuels and postpone combustion;
- Tetrahedrite is applied in the manufacturing of electric wiring and silver-based inks used to create electrical pathways in electronics. It also supports photovoltaic cells in their transformation of the sunlight into electric power. In addition, this antimony compound is used in making jewelry, mirrors, coins, etc.
Hydrated Potassium Antimonyl Antimonate (Tartar Emetic)
The tartar emetic [K2Sb2(C4H2O6)2], also labeled as antimony potassium tartrate, potassium antimontarterate, potassium antimontarterate, or potassium antimonyl tartrate, is a chemical compound used in medicine since the Middle Ages for its strong emetic (vomiting triggering) properties.
What is Tartaric Acid?
The tartaric acid (also called dihydroxybutanedioic acid) is a white, crystalline organic acid. It is one of the main components of the emetic tartar that is mainly obtained from the by-products of wine fermentation. The Swedish chemist Carl Wilhelm Scheele was the first scientist who succeeded in isolating this plant acid from the grapes in 1769. Tartaric acid naturally occurs in many other fruits, such as bananas, tamarinds, lemons, apricots, oranges, limes, kumquat, pomelo, tangerine, etc.
There are three stereoisomeric forms of tartaric acid:
- Dextrorotatory tartaric acid (D-tartaric acid);
- Levorotatory tartaric acid (L-tartaric acid);
- A meso or achiral form of tartaric acid.
Apart from being used for the preparation of tartar emetic, tartaric acid also has wide industrial application as an acidulant in carbonated drinks, gelatin desserts, fruit jellies, effervescent tablets, etc. In addition, cream of tartar (a salt of tartaric acid) is found in foods and food additives, such as baking powders, taffies, and hard candies.
Preparation of Emetic Tartar during the Middle Ages
The formula [K2Sb2(C4H2O6)2] represents a double salt of potassium and antimony of tartaric acid. This antimony compound was first described by the German alchemist Adrian von Mynsicht (1603–1638), in 1631. He prepared the emetic tartar by boiling three parts of argentine flowers of antimony (a form of antimony oxide) with four parts of cream of tartar (potassium hydrogen tartrate). After an hour, von Mynsicht would filter the solution. After most of the water would evaporate and the solution would cool, crystals of antimony potassium tartrate would grow.
Many antiparasitic remedies were developed according to the aforedescribed von Mynsicht’s recipe. They were widely used for treating trichinosis, leishmaniasis, schistosomiasis, and trypanosomiasis under the labels: Dr. J. Johnson’s pills, Hind’s sweating ball (a veterinarian preparation), Mitchell’s pills, etc. The Roman physician Galen and the Swiss alchemist Paracelsus were among the most vocal advocates for the medicinal use of this antimony compound.
Tartar Emetic in the Conventional Medicine
Conventional medicine uses tartar emetic (antimony and potassium tartrate) as an expectorant and a nauseant to provoke vomiting, as well as in the treatment of patients with helminthic and fungal infestations.
How Dangerous Is Antimony?
Human exposure to antimony can occur when inhaling polluted air, drinking contaminated water, eating foods that contain antimony, as well as by skin contact with contaminated soil or surface waters.
The health dangers of antimony can be observed via two main aspects of exposure to this toxic substance:
- Occupational exposure, and
- Therapeutic exposure.
Occupational Exposure to Antimony
According to the United States National Library of Medicine, National Institutes of Health, the prolonged occupational exposure of industry or port workers to high levels of antimony via inhalation to some of its toxic compounds, dust, or particles of the antimony metal may lead to antimony toxicity. The affected individuals typically experience adverse health effects, such as:
- Kidney damage;
- Severe bouts of coughing,
- Gastro-intestinal problems;
- Appearance of antimony spots on the skin;
- Chronic bronchitis;
- Chronic emphysema;
- Inactive tuberculosis;
- Pleural adhesions;
- Irritation of the breathing pathways;
- Cognitive problems;
- An increased risk of spontaneous abortion in women;
- Adams-Stokes Syndrome.
Therapeutic Exposure to Antimony
Since ancient times, patients suffering from parasitic infections, such as schistosomiasis and leishmaniasis, were treated with the toxic antimony compounds in oxidation state III, as well as with compounds containing Sb in the oxidation state V [such as antimony sodium gluconate (pentostam), or meglumine antimonite (glucantime)].
Despite being used for a beneficial cause health-wise, the aforementioned poisonous antimony compounds can also raise the antimony concentration in blood, and thus lead to damage of the pancreas or cardiotoxicity.
Namely, conventional medicine uses tartar emetic as a therapy in patients who have abused alcohol. According to a study, prolonged treatment with this antimony compound in the treatment of alcohol abuse may lead to a severe form of antimony poisoning, manifested with vomiting, diarrhea, and stomatitis that could further lead to other gastrointestinal complications.
Antimony as a Carcinogen
The studies on antimony trioxide and antimony trisulfide toxicity have shown that these substances may trigger the formation of lung tumors in rats. The International Agency for Research on Cancer has also classified antimony trioxide as a possibly carcinogenic substance to humans (Group 2B).
In humans, it has been observed that antimony trioxide causes pneumoconiosis (an interstitial lung disease caused by inhalation of certain kinds of dust particles that damage the lungs).
Environmental Effects of Antimony
As per the studies conducted by the Environmental Protection Agency, antimony can be found in very small amounts everywhere in our environment, even in food. Antimony and its compounds are considered to be priority pollutants as a result of both natural processes and human activities.
In the geosphere, biosphere, and the aquatic systems of our environment, antimony occurs mainly in the form of Sb(III) and Sb(V) – compounds that are highly toxic and classified as carcinogens. In the environment, these antimony compounds mainly pollute the soil.
Isotopes of Antimony
There are 36 isotopes of antimony observed. Thirty-five of them are synthetically produced 125Sb radioisotopes. All isotopes of antimony undergo a beta+ or beta- decay mode to Sn (tin), In (indium), or Te (tellurium).
The naturally occurring 51Sb is composed of two stable isotopes: 121Sb and 123Sb. Having a half-life of 2.75856 years, the 125Sb radioisotope is the longest living form of element 51.
|Z||N||Isotopic mass (Da)
[n 2][n 3]
[n 5][n 6]
[n 7][n 8]
|Natural abundance (mole fraction)|
|Excitation energy[n 8]||Normal proportion||Range of variation|
|103Sb||51||52||102.93969(32)#||100# ms [>1.5 µs]||β+||103Sn||5/2+#|
|β+, p (7%)||103In|
|105Sb||51||54||104.93149(11)||1.12(16) s||β+ (99%)||105Sn||(5/2+)|
|β+, p (<1%)||104In|
|β+, p (rare)||107In|
|122Sb||51||71||121.9051737(24)||2.7238(2) d||β− (97.59%)||122Te||2−|
|135Sb||51||84||134.92517(11)||1.68(2) s||β− (82.4%)||135Te||(7/2+)|
|β−, n (17.6%)||134Te|
|136Sb||51||85||135.93035(32)#||0.923(14) s||β− (83%)||136Te||1−#|
|β−, n (17%)||135Te|
|138Sb||51||87||137.94079(32)#||500# ms [>300 ns]||β−||138Te||2−#|
|139Sb||51||88||138.94598(54)#||300# ms [>300 ns]||β−||139Te||7/2+#|
List of Antimony Compounds
When antimony becomes a part of a chemical compound, it usually adopts the oxidation state +3 or +5. Respectively, the compounds of this chemical element are classified according to their oxidation state: Sb (III), or Sb (V).
Antimony forms halides, oxides, hydroxides, hydrides, as well as antimonides. In addition, organoantimony compounds are prepared by combining Grignard reagents with antimony halides:
The list of most often prepared antimony compounds contains the following items:
- Antimony oxychloride
- Antimony pentachloride
- Antimony pentafluoride
- Antimony pentasulfide
- Antimony pentoxide
- Antimony potassium tartrate
- Antimony sulfate
- Antimony telluride
- Antimony tetroxide
- Antimony tribromide
- Antimony trichloride
- Antimony trifluoride
- Antimony triiodide
- Antimony trioxide
- Antimony triselenide
- Antimony trisulfide
- Antimony(III) acetate
- Fluoroantimonic acid
- Gallium indium arsenide antimonide phosphide
- Indium arsenide antimonide phosphide
- Magic acid
- Meglumine antimoniate
- Pentavalent antimonial
- Sodium stibogluconate
- Sodium thioantimoniate
- Titanium yellow
- Tris(4-bromophenyl)ammoniumyl hexachloroantimonate
5 Interesting Facts and Explanations
- Allotropes are physically distinct forms or aggregate states of a chemical element that are made by rearrangement of the same atoms in molecules or crystals.
- Upon cooling, antimony and some of its alloys may expand.
- The first visual association upon hearing the name of Cleopatra are her eyes underlined with kohl, i.e. antimony sulfide. In ancient Egypt, it was believed that exaggerated eyes are a symbol of beauty. Boldly underlined eyes also indicated a higher social rank and achievements. For this, people of Ancient Egypt also used green malachite and black galena along with the kohl.
- The favourite remedy of the most famous alchemist of the German renaissance, Paracelsus, contained antimony. It was an alcoholic solution made of the nitrates and tartrates of antimony (4 parts), tin (1 part), and copper (1 part) that he considered to be a universal cure for many ailments.
- “Argentine flowers of antimony” refers to a form of antimony trioxide (Sb2O3) found in the minerals valentinite and senarmontite.