Antimony

2008/9 Schools Wikipedia Selection. Related subjects: Chemical elements

51 tin ← antimony → tellurium As ↑ Sb ↓ Bi Periodic Table - Extended Periodic Table
General
Name, Symbol, Number	antimony, Sb, 51
Chemical series	metalloids
Group, Period, Block	15, 5, p
Appearance	silvery lustrous gray
Standard atomic weight	121.760 (1)  g·mol−1
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·cm−3
Liquid density at m.p.	6.53  g·cm−3
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−1
Heat of vaporization	193.43   kJ·mol−1
Specific heat capacity	(25 °C) 25.23  J·mol−1·K−1
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−1
	2nd:  1594.9  kJ·mol−1
	3rd:  2440  kJ·mol−1
Atomic radius	145   pm
Atomic radius (calc.)	133  pm
Covalent radius	138  pm
Miscellaneous
Magnetic ordering	no data
Electrical resistivity	(20 °C) 417 n Ω·m
Thermal conductivity	(300 K) 24.4  W·m−1·K−1
Thermal expansion	(25 °C) 11.0  µm·m−1·K−1
Speed of sound (thin rod)	(20 °C) 3420 m/s
Young's modulus	55  GPa
Shear modulus	20  GPa
Bulk modulus	42  GPa
Mohs hardness	3.0
Brinell hardness	294  MPa
CAS registry number	7440-36-0
Selected isotopes
Main article: Isotopes of antimony iso NA half-life DM DE ( MeV) DP 121Sb 57.36% 121Sb is stable with 70 neutrons 123Sb 42.64% 123Sb is stable with 72 neutrons 125Sb syn 2.7582 y Beta- 0.767 125Te
References

Antimony (pronounced /ˈæntɪmoʊni/ (US), /ˈæntɪməni/ (UK)) is a chemical element with the symbol Sb (Latin: stibium, meaning "mark") and atomic number 51. A metalloid, antimony has four allotropic forms. The stable form of antimony is a blue-white metalloid. Yellow and black antimony are unstable non-metals. Antimony is used in flame-proofing, paints, ceramics, enamels, a wide variety of alloys, electronics, and rubber.

Properties

Antimony in its elemental form is a silvery white, brittle, fusible, crystalline solid that exhibits poor electrical and heat conductivity properties and vaporizes at low temperatures. A metalloid, antimony resembles a metal in its appearance and in many of its physical properties, but does not chemically react as a metal. It is also attacked by oxidizing acids and halogens. Antimony and some of its alloys are unusual in that they expand on cooling. Antimony is geochemically categorized as a chalcophile, occurring with sulfur and the heavy metals lead, copper, and silver.

Estimates of the abundance of antimony in the Earth's crust range from 0.2 to 0.5 ppm. According to New Scientist ( 26 May 2007) the earth has an estimated thirty years supply left of this element; however, with anticipated increases in demand the supply could be exhausted in 15 years.

Applications

Antimony is increasingly being used in the semiconductor industry in the production of diodes, infrared detectors, and Hall-effect devices. As an alloy, this metalloid greatly increases lead's hardness and mechanical strength. The most important use of antimony is as a hardener in lead for storage batteries. Uses include:

• Batteries
• antifriction alloys
• type metal
• small arms and tracer ammunition
• cable sheathing
• matches
• medicines, antiprotozoan drugs
• plumbing
• soldering - some "lead-free" solders contain 5% Sb
• main and big-end bearings in internal combustion engines (as alloy)
• used in the past to treat Schistosomiasis; today Praziquantel is universally used
• used in linotype printing machines

Antimony compounds in the form of 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. It is also used in the fibreglass composites industry as an additive to polyester resins for such items as light aircraft engine covers. The resin will burn while a flame is held to it but will extinguish itself as soon as the flame is removed. Antimony sulfide is also one of the ingredients of safety matches.

In the 1950s, tiny beads of a lead-antimony alloy were used for the emitters and collectors of NPN alloy junction transistors.

The natural sulfide of antimony, stibnite, was known and used in Biblical times as medicine and as a cosmetic. Stibnite is still used in some developing countries as medicine. Antimony has been used for the treatment of schistosomiasis. Antimony attaches itself to sulfur atoms in certain enzymes which are used by both the parasite and human host. Small doses can kill the parasite without causing damage to the patient. Antimony and its compounds are used in several veterinary preparations like Anthiomaline or Lithium antimony thiomalate, which is used as a skin conditioner in ruminants. Antimony has a nourishing or conditioning effect on keratinized tissues, at least in animals. Tartar emetic is another antimony preparation which is used as an anti-schistosomal drug. Treatments chiefly involving antimony have been called antimonials.

A coin made of antimony was issued in the Keichow Province of China in 1931. The coins were not popular, being too soft and they wore quickly when in circulation. After the first issue no others were produced.

Etymology

The ancient words for antimony mostly have, as their chief meaning, kohl, the sulfide of antimony. Pliny the Elder, however, distinguishes between male and female forms of antimony; his male form is probably the sulfide, the female form, which is superior, heavier, and less friable, is probably native metallic antimony.

The Egyptians called antimony mśdmt; in hieroglyphics, the vowels are uncertain, but there is an Arabic tradition that the word is mesdemet. The Greek word, stimmi, is probably a loan word from Arabic or Egyptian, and is used by the Attic tragic poets of the 5th century BC; later Greeks also used stibi, as did Celsus and Pliny, writing in Latin, in the first century AD. Pliny also gives the names stimi [sic], larbaris, alabaster, and the "very common" platyophthalmos, "wide-eye" (from the effect of the cosmetic). Later Latin authors adapted the word to Latin as stibium. The Arabic word for the substance, as opposed to the cosmetic, can appear as ithmid, athmoud, othmod, or uthmod. Littré suggests the first form, which is the earliest, derives from stimmida, (one) accusative for stimmi.

The use of Sb as the standard chemical symbol for antimony is due to the 18th century chemical pioneer, Jöns Jakob Berzelius, who used this abbreviation of the name stibium.

The medieval Latin form, from which the modern languages, and late Byzantine Greek, take their names, is antimonium. The origin of this is uncertain; all suggestions have some difficulty either of form or interpretation. The popular etymology, from anti-monachos or French antimoine, still has adherents; this would mean "monk-killer", and is explained by many early alchemists being monks, and antimony being poisonous. So does the hypothetical Greek word antimonos, "against one", explained as "not found as metal", or "not found unalloyed". Lippmann conjectured a Greek word, anthemonion, which would mean "floret", and he cites several examples of related Greek words (but not that one) which describe chemical or biological efflorescence.

The early uses of antimonium include the translations, in 1050-1100, by Constantine the African of Arabic medical treatises. Several authorities believe that antimonium is a scribal corruption of some Arabic form; Meyerhof derives it from ithmid; other possibilities include Athimar, the Arabic name of the metal, and a hypothetical *as-stimmi, derived from or parallel to, the Greek.

History

Antimony's sulfide compound, antimony (III) trisulfide, Sb₂S₃ was recognized in antiquity, at least as early as 3000 BC. Pastes of Sb₂S₃ powder in fat or in other materials have been used since that date as eye cosmetics in the Middle East and farther afield; in this use, Sb₂S₃ is called kohl. It was used to darken the brows and lashes, or to draw a line around the perimeter of the eye.

An artifact made of antimony dating to about 3000 BC was found at Tello, Chaldea (part of present day Iraq), and a copper object plated with antimony dating between 2500 BC and 2200 BC has been found in Egypt. There is some uncertainty as to the description of the artifact from Tello. Although it is sometimes reported to be a vase, a recent detailed discussion of it reports it to be rather a fragment of indeterminate purpose.

According to the history of metallurgy, the first description of a procedure for isolating antimony is in the book De la pirotechnia of 1540 by Vannoccio Biringuccio, written in Italian. This book precedes the more famous 1556 book in Latin by Agricola, De re metallica, even though Agricola has been often incorrectly credited with the discovery of metallic antimony.

Alchemical symbol for antimony

According to the traditional history of western alchemy, metallic antimony was described (previous to Biringuccio) by the putative Prior Basilius Valentinus in a Latin manuscript, Currus Triumphalis Antimonii, supposedly circa 1450. This manuscript was published in 1604 in English translation as The Triumphal Chariot of Antimony, by Johann Thölde (1565–1614). The marvelous discovery of a complete set of Valentinus' manuscripts, including the alchemical tales, is fully described by Jean-Jacques Manget in his Bibliotheca chemica curiosa (1702): the manuscripts had been enclosed for more than a century in a pillar of St. Peter's Abbey, at Erfurt, until the pillar was shattered by a thunderbolt. Many scholars have considered Basilius Valentinus a mythological personage. Gottfried Wilhelm Leibniz (1646–1716) declared, after careful enquiry, that no Prior Valentinus ever existed in the Abbey of Erfurt, rather that the name was only a pseudonym – probably of Thölde himself – used to merge poorly translated materials of various origins.

According to the traditional history of Middle Eastern alchemy, pure antimony was well known to Geber, sometimes called "the Father of Chemistry", in the 8th century. Here there is still an open controversy: Marcellin Berthelot, who translated a number of Geber's books, stated that antimony is never mentioned in them, but other authors claim that Berthelot translated only some of the less important books, while the more interesting ones (some of which might describe antimony) are not yet translated, and their content is completely unknown.

Precautions

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.

A study found that antimony may be leaching from PET bottled water, but at levels below drinking water guidelines. The guidelines are:

• WHO, 20 µg l^–1
• Japan, 15 µg l^–1
• US EPA, Health Canada and the Ontario Ministry of Environment, 6 µg l^–1
• German Federal Ministry of Environment, 5 µg l^–1

The acidic nature of the drink is sufficient to dissolve small amounts of antimony oxide contained in the packaging of the drink; modern manufacturing methods prevent this occurrence. However, researchers are concerned that antimony levels correspond to duration the bottle is left to stand - the longer the beverage has been bottled, the higher the antimony leached.

Chemistry

Important compounds of antimony include:

• Antimony pentafluoride SbF₅
• Antimony trioxide Sb₂O₃
• Stibine (antimony trihydride SbH₃)
• Indium antimonide (InSb)
• Fluoroantimonic acid (HSbF₆)