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What is Antimony

Antimony (pronunciation: AN-te-MOH-nee) is a lustrous metallic element that belongs to the family of metalloids and is represented by the chemical symbol Sb [1, 2, 3]. There are two stable isotopes of antimony, including 121Sb and 123Sb with a natural abundance of 57.21% and 42.79% respectively [4]. It also has 35 artificially-produced radioactive isotopes, out of which the longest-lived are 125Sb, 124Sb, and 126Sb with half-lives of 2.75856 years, 60.2 days, and 12.35 days respectively [4].


Where is Antimony Found

Antimony occurs naturally in trace amounts in more than 100 types of mineral ores, mainly from antimony (III) sulfide (stibnite) [1, 5]. It is commercially obtained by roasting antimony trisulfide to form antimony oxide and then reducing it with carbon [1]. Antimony is also found in its native form [1]. China, Bolivia, and Tajikistan are the top 3 producers while China, Russia, and Bolivia have the largest antimony reserves in the world [1].


Origin of its Name: The name is derived from ‘anti-monos’, a Greek word that means “opposed to solitude” or “against solitude” [1, 6].

Who discovered it: Since a 5000-year-old vase made of pure antimony is shown in the Louvre museum, the element was probably found by the ancient people thousands of years ago [1].

When and How was it Discovered

The early use of antimony sulfide (Sb2S3) has been recorded in an Egyptian papyrus dating back to 1600 BC [1]. Its mineral ore, stibnite, was commonly used in its black form as mascara by the ancient people notably by the temptress Jezebel [1].

Lead antimonate, a yellowish pigment was used by the Chaldean craftsmen during 600-500 BC [1]. It was used in the thin coating of ornamental bricks found at Babylon made during the reign of Nebuchadnezzar from 604 to 561 BC [1].

Antimony Symbol

In the Medieval times, it was widely used for hardening lead while some were taken as a laxative [1].

Antimony Identification

Atomic number 51 [1]
CAS number 7440-36-0 [1]
Position in the periodic table Group Period Block
  15 [1] 5 [1] p [1]

Properties and Characteristics of Antimony

General Properties

Relative atomic mass 121.760 [1]
Atomic mass 121.760 amu [1]
Molar mass 121.7600 g/mol [7]
Molecular weight 121.76 g/mol [2]
Allotropes White Sb, Black Sb, Yellow Sb [1]

Physical Properties

Color Silvery-white [2, 8]
Melting point/freezing point 630.628 °C, 1167.13 °F [1]
Boiling point 1587 °C, 2889 °F [1]
Density 6.68 g cm-3 [1]
State of matter at room temperature (solid/liquid/gas) Solid [1, 8]
– Brinell 294 MPa [9]
– Mohs 3 [9]
– Vickers Unknown [9]
Electrical Conductivity 2.5 X 106 S/m [9]
Charge -3, +5 [10]
Thermal (heat) conductivity 24 W/(m K) [9]
Specific heat 207 J kg-1 K-1 [1]
Bulk modulus 42 GPa [1]
Shear modulus Unknown [1]
Young’s modulus Unknown [1]
Vapor pressure
– Temperature (K) 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400
– Pressure (Pa)

Chemical Properties

Oxidation states 5, 3, -3 [1]
Isotopes Isotope Mass Abundance (%) Half-life Mode of decay
  121Sb 120.904 57.21
  123Sb 122.904 42.79

Antimony Lewis Dot Structure

Atomic Data of Antimony (Element 51)

Valence electrons 5 [11]
Quantum numbers
– n 5 [11]
– ℓ 1 [11]
– m 1 [11]
– ms +1/2 [11]
Electron configuration (noble gas configuration) [Kr] 4d105s25p3 [1]
Atomic structure
– Number of electrons 51 [8]
– Number of neutrons 70 [8]
– Number of protons 51 [8]
Radius of Atom
– Atomic radius 2.06 Å [1]
– Covalent radius 1.40 Å [1]
Electronegativity (Pauling-scale) 2.05 [1]
Electron affinity 100.924 [1]
Ionization energy (kJ mol-1) 1st 2nd 3rd 4th 5th 6th 7th 8th
  830.583 1604.55 2441.1 4264.7 5403 10420

Antimony Electron Configuration (Bohr Model)

What is it Used for

  • It is used for producing some semiconductor devices, including diodes and infrared detectors [1].
  • It is mixed with lead and other metals to form alloys that increase the metals’ strength, hardness, and durability [1, 3]. While antimony-lead alloy is commonly used in car batteries, antimony alloys are also used in cable sheathing, casting bullets, and making type characters in printing presses [1].
  • Compounds of antimony are used for manufacturing flame-resistant materials, paints, enamels, pottery and glass [1].
  • An alloy of antimony, lead, tin, and copper, called Babbit metal, is used in making machinery bearings for its hardness and slipperiness [8].

Antimony Trisulfide (Stibnite)

Antimony Toxicity

It occurs either during the treatment of parasitic diseases, including schistosomiasis and leishmaniasis or because of occupational exposure [12]. Also, antimony trioxide is considered to be carcinogenic to humans [12]. Exposure to antimony compounds like antimony trisulfide, antimony tribromide, antimony pentasulfide, etc. may cause respiratory, gastrointestinal, cardiovascular, reproductive, and dermal effects [12].

Interesting Facts

  • The stibnite crystals, resembling a group of swords and made from sulfur and antimony, were auctioned on 2nd June 2013 with an opening bidding price of $32,500 [5]. The mineral, measuring 9 X 10 X 4 inches, was obtained from the Lushi Mine, China [5].
  • Antimony is graphically represented by the Eye of Horus, a symbol of royal power, good health, and protection from ancient Egypt [1]. It also indicates the use of antimony sulfide as eye makeup [1].
  • It is stable in air and water, being slightly oxidized by air and insoluble in water [2].
  • In the pure form, it is neither ductile nor malleable like true metals [14].

Antimony Element 51

Price of Antimony

The cost of pure antimony is about $0.045 per gram, and in bulk, it costs about $0.0044 per gram [8]. In July 2018, the average price of antimony per metric ton is $8,294 [13].



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