Antimony

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51 tinantimonytellurium
As

Sb

Bi
Sb-TableImage.png
General
Name, Symbol, Number antimony, Sb, 51
Chemical series metalloids
Group, Period, Block 15, 5, p
Appearance silvery lustrous grey
Sb,51.jpg
Atomic mass 121.760(1) g/mol
Electron configuration [Kr] 4d10 5s2 5p3
Electrons per shell 2, 8, 18, 18, 5
Physical properties
Phase solid
Density (near r.t.) 6.697 g/cm³
Liquid density at m.p. 6.53 g/cm³
Melting point 903.78 K
(630.63 °C, 1167.13 °F)
Boiling point 1860 K
(1587 °C, 2889 °F)
Heat of fusion 19.79 kJ/mol
Heat of vaporization 193.43 kJ/mol
Heat capacity (25 °C) 25.23 J/(mol·K)
Vapor pressure
P/Pa 1 10 100 1 k 10 k 100 k
at T/K 807 876 1011 1219 1491 1858
Atomic properties
Crystal structure rhombohedral
Oxidation states −3, 3, 5
Electronegativity 2.05 (Pauling scale)
Ionization energies
(more)
1st: 834 kJ/mol
2nd: 1594.9 kJ/mol
3rd: 2440 kJ/mol
Atomic radius 145 pm
Atomic radius (calc.) 133 pm
Covalent radius 138 pm
Miscellaneous
Magnetic ordering no data
Electrical resistivity (20 °C) 417 nΩ·m
Thermal conductivity (300 K) 24.4 W/(m·K)
Thermal expansion (25 °C) 11.0 µm/(m·K)
Speed of sound (thin rod) (20 °C) 3420 m/s
Speed of sound (thin rod) (r.t.) 55 m/s
Shear modulus 20 GPa
Bulk modulus 42 GPa
Mohs hardness 3.0
Brinell hardness 294 MPa
CAS registry number 7440-36-0
Notable isotopes
Main article: Isotopes of antimony
iso NA half-life DM DE (MeV) DP
121Sb 57.36% Sb is stable with 70 neutrons
123Sb 42.64% Sb is stable with 72 neutrons
125Sb syn 2.7582 y Beta- 0.767 125Te

Antimony (chemical symbol Sb, atomic number 51) is a metalloid with four allotropic forms. The stable form of antimony is a blue-white metal. Yellow and black antimony are unstable nonmetals. Antimony and many of its compounds are toxic and need to be handled with care.

This element is mainly used as a hardener in lead for storage batteries. In addition, it is used in alloys for type metal, tracer bullets, antifriction materials, cable sheathing, plumbing, and solder. Recently, it is being used by the semiconductor industry for the manufacture of diodes and infrared detectors. Several compounds of antimony are used in the production of flame-proofing materials, glasses, ceramics, paints, and pottery. Some compounds have a history of use as medicines for humans and animals.

Contents

Etymology

The derivation of antimony's modern name and its symbol can be traced along a complex path. Antimony sulfide (Sb2S3) was used in some countries as a cosmetic powder, and its Coptic name (CTHM, or "stem") was borrowed by the Greeks, who called it στιβι (stibi). From that came the Latin name stibium, which was then converted in Arabic to انتيمون ([al-]ithmīd). Al-ithmīd, in turn, was later latinized by alchemists to "athimodium," and eventually to "antimonium." The chemical pioneer Jöns Jakob Berzelius abbreviated stibium as Sb in his writings about antimony, and his abbreviation became the standard symbol.

Occurrence

Native, massive antimony, with oxidation products.

Estimates of the abundance of antimony in the Earth's crust range from 0.2 to 0.5 parts per million (ppm). Despite this low abundance, it is found in over 100 mineral species. It is sometimes found in the native (elemental) state, but it occurs predominantly as the sulfide mineral stibnite (Sb2S3). It is also found associated with lead, copper, and silver.

The People's Republic of China is by far the world's largest producer of antimony. The largest mine in that country is the Xikuangshan mine in Hunan Province. Other producers are Russia, South Africa, Tajikistan, and Bolivia.

Commercially, antimony is generally produced in the form of ingots, broken pieces, granules, and cast cake. Other forms are powder, shot, and single crystals.

Country Metric tons  % of total
People's Republic of China 126 000 81.5
Russia 12 000 7.8
South Africa 5 023 3.3
Tajikistan 3 480 2.3
Bolivia 2 430 1.6
Top 5 148 933 96.4
Total world 154 538 100.0

Chiffres de 2003, métal contenue dans les minerais et concentrés, source: L'état du monde 2005

History

Antimony was recognized in antiquity (3000 B.C.E. or earlier) in various compounds and was prized for its fine casting qualities. The black powder of antimony sulfide (stibium) is soluble in water and was the ancient version of mascara during Roman times. It was used to darken eyebrows and eyelashes, or to draw a line around the perimeter of the eye.

Alchemical symbol for antimony.

In the traditional history of Middle Eastern alchemy, it is claimed that pure antimony was well-known to the Islamic alchemist Geber (Abu Musa Jabir ibn Hayyan) in the eighth century. This claim, however, is disputed. Marcellin Berthelot, who translated a number of Geber's books, stated that antimony is never mentioned in them. Other authors, however, state that Berthelot translated only some of the less important books, while the more interesting ones (some of which might describe antimony) have yet to be translated.

According to the history of metallurgy, the first description of the procedure to isolate antimony is in the Italian book De la pirotechnia by Vannoccio Biringuccio, published in 1540. This book precedes the more famous Latin book De re metallica of 1556 by Agricola, although the latter has often been incorrectly considered the discoverer of metallic antimony.

The traditional history of Western alchemy maintains that metallic antimony was described (before Biringuccio's book) by the Prior Basilius Valentinus, in the Latin manuscript "Currus Triumphalis Antimonii" of about 1450. It was published in the English translation, "The triumphal chariot of antimony," in 1604, by Johann Thölde (1565-1614). The marvelous finding of all of the Valentinus' manuscripts, as in the alchemical tales, is fully described by Jean-Jacques Manget in his Bibliotheca chemica curiosa (1702). These manuscripts remained enclosed for more than a century in a pillar of Saint Peter's Abbey at Erfurt, until the pillar was shattered by a thunderbolt.

Some scholars have considered Basilius Valentinus a mythological personage. The most prominent critic was Leibniz (1646-1716), who declared after a careful search that the Prior Valentinus never existed in the Abbey of Erfurt, but was only a pseudonym, probably of Thölde himself, used to merge poorly translated materials of various origins.

Notable characteristics

In the periodic table, antimony is located in group 15 (formerly group 5A), between arsenic and bismuth. It is thus a member of the nitrogen family of elements, sometimes called the pnictogens (or pnicogens). It lies in period 5, between tin and tellurium.

In its elemental form, antimony is a silvery white, brittle, fusible, crystalline solid. It exhibits poor electrical and thermal conductivity and vaporizes at low temperatures. A metalloid, antimony resembles a metal in appearance and physical properties, but chemically it does not react as a metal. It is attacked by oxidizing acids and halogens. Antimony and some of its alloys are unusual in that they expand on cooling.

Isotopes

Antimony has multiple isotopes, only two of which are stable: 121Sb and 123Sb. Their relative abundances have been calculated to be about 57.36 percent and 42.64 percent, respectively. The radioactive isotope 125Sb has a half-life of about 2.76 years, but the other radioisotopes have extremely short half-lives.

Compounds

  • Antimony pentafluoride (SbF5): This colorless, viscous liquid is a valuable Lewis acid and a component of fluoroantimonic acid, the strongest known acid (a superacid). It therefore reacts with almost all known compounds.[1] In many cases, the reaction is violent, producing dangerous hydrogen fluoride.
  • Antimony trioxide (Sb2O3): It is the most important commercial compound of antimony. Its industrial preparation mainly involves roasting antimonide minerals. It is used as: a flame retardant for textiles and polymers; a pigment; and an opacifying agent for glasses, ceramics and enamels. This compound is only weakly absorbed by the digestive system, and the main route of exposure is by inhalation of the dust. Acute poisoning is rare, and the signs are fairly noncharacteristic (vomiting, abdominal pain, irritation of the mucous membranes, diarrhea, cardiac irregularities). Long-term exposure leads to chronic toxicity, indicated by irritation of skin and respiratory tract, with a characteristic pneumoconosis visible on chest X rays. Antimony trioxide is known to pass into breast milk and to traverse the placenta.
  • Stibine, stibane, or antimony trihydride (SbH3): This colorless gas is the principal covalent hydride of antimony and a heavy analog of ammonia. It is flammable and highly toxic, but it is so unstable that it is rarely encountered. It is generally prepared by the reaction of Sb3+ sources with hydride (H) equivalents. The gas decomposes slowly at room temperature but rapidly at 200°C. It is used in the semiconductor industry to dope small quantities of antimony by the process known as chemical vapor deposition (CVD).
  • Indium antimonide (InSb): This crystalline compound is a narrow-gap semiconductor material. It is used in infrared detectors, including thermal-imaging cameras, infrared homing missile guidance systems, and instruments for infrared astronomy.

Applications

The most important use of antimony is as a hardener in lead for storage batteries. In addition, antimony is increasingly being used in the semiconductor industry in the production of diodes, infrared detectors, and Hall-effect devices.

Antimony (particularly as an alloy) is also used in:

  • antifriction alloys
  • type metal
  • small arms and tracer bullets
  • cable sheathing
  • plumbing
  • soldering (some "lead-free" solders contain 5 percent antimony)
  • main and big-end bearings in internal combustion engines
  • linotype printing machines

Antimony compounds—particularly the oxides, sulfides, sodium antimonate, and antimony trichloride—are used in the making of flame-proofing compounds, ceramic enamels, glass, paints, and pottery. Antimony trioxide is the most important of the antimony compounds and is primarily used in flame-retardant formulations. These flame-retardant applications include such markets as children's clothing, toys, aircraft and automobile seat covers. Also, antimony sulfide is one of the ingredients in modern matches.

Medical uses

  • Stibnite, the natural sulfide of antimony, was known and used in Biblical times as medicine, and it is still used as such in some developing countries.
  • Antimony was used in the past for the treatment of schistosomiasis, but it has been replaced by another drug (Praziquantel). Antimony attaches itself to the sulfur atoms of certain enzymes that are used by both the parasite and human host. Small doses can kill the parasite without significantly harming the patient.
  • Antimony and its compounds are used in several veterinary preparations. For instance, Anthiomaline or Lithium antimony thiomalate is used as a skin conditioner in ruminants. Antimony has a nourishing or conditioning effect on keratinized tissues, at least in animals.

Precautions

Skull and crossbones.svg

Antimony and many of its compounds are toxic. Clinically, antimony poisoning is very similar to arsenic poisoning. In small doses, antimony causes headache, dizziness, and depression. Larger doses cause violent and frequent vomiting, and will lead to death in a few days.

In the past, small doses have been reported in some acidic fruit drinks. The acidic nature of the drink was sufficient to dissolve small amounts of antimony oxide in the packaging for the drink. Modern manufacturing methods, however, avoid this problem. Also, a study has found that antimony is leached from polyethylene terephthalate (PET) bottles, but at levels below drinking water guidelines.

The guidelines for maximum permissible levels of antimony in drinking water are as follows.[2]

  • World Health Organization (WHO): 20 micrograms per liter (ug/L)
  • U.S. EPA, Health Canada, and the Ontario Ministry of Environment: 6 ug/L
  • German Federal Ministry of Environment: 5 ug/L
  • Japan: 2 ug/L

Footnotes

  1. G. A. Olah, G.K.S. Prakash, Q. Wang, X.-y Li. "Antimony(V) Fluoride" in Encyclopedia of Reagents for Organic Synthesis, Ed. L. Paquette. (New York: J. Wiley & Sons, 2004.)
  2. Shotyk, William; Krachler, Michael; Chen, Bin Contamination of Canadian and European bottled waters with antimony from PET containers J. Environ. Monit 8(2006): 288-292 DOI: 10.1039/b517844b

References

all refs Retrieved December 28, 2007.

See also

External links

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