Antimony

General:

Name:Antimony Symbol:Sb
Type:Metalloid, Nitrogen group Atomic weight:121.75
Density @ 293 K:6.684 g/cm3 Atomic volume:18.22 cm3/mol
Discovered:

The presence of antimony in historical artifacts indicates it was known to ancient civilizations. Combined with sulfur in stibnite (Sb2S3) it was used in Egyptian cosmetics four or five thousand years ago, as a black eyeliner.(1)

It's likely that Roman author Pliny gave it the name stibium, from which the modern element symbol Sb was taken, in the first century AD. Stibnite is found most commonly, Pliny says, among the ores of silver. Pliny described stibnite's use as a medicine. He also noted how if too strongly heated, it would turn to lead. What we understand now by this is the lead described by Pliny is actually the element antimony. (2)

In the first half of the 1500s, Vannoccio Biringuccio wrote a description "Concerning Antimony and Its Ore". This is an alchemical work. Biringuccio describes antimony sulfide as either "a monstrosity among metals" or, alternatively, "a material that is about to reach metallic perfection, but is hindered from doing so by being mined too soon". He also warns against heating the antimony sulfide too strongly because this will produce a substance that "although this is very white and almost more shining than silver, it is much more brittle than glass." This is a clear description of the element antimony. (3)

Nicolas Lémery wrote his Treatise on Antimony in 1707. This was still not chemistry as we know it. In his writings, Lémery describes how acids prick the tongue because they contain spiky particles, while metals dissolve in acids because the sharp points of acids tear the metal particles apart. (4)

The name "antimony" is derived from two Greek words: 'anti' and 'monos' which mean not alone. This results from the fact that antimony is infrequently found native, but usually combined with sulfur or with heavier metals such as copper, lead and silver.

States

State (s, l, g):solid
Melting point:903.94 K (630.79 °C) Boiling point:1860 K (1587 °C)

Energies

Specific heat capacity: 0.21 J/gK Heat of atomization: 262 kJ mol-1
Heat of fusion:19.870 kJ mol-1 Heat of vaporization : 67.97 kJ mol-1
1st ionization energy: 833.7 kJ mol-1 2nd ionization energy:1594.9 kJ mol-1
3rd ionization energy:2441.1 kJ mol-1 Electron affinity:103 kJ mol-1

Oxidation & Electrons

Shells:2,8,18,18,5 Electron configuration: [Kr] 4d10 5s2 5p3
Minimum oxidation number: -3 Maximum oxidation number:5
Min. common oxidation no.:0 Max. common oxidation no.:5
Electronegativity (Pauling Scale):2.05 Polarizability volume:6.6 Å3

Appearance & Characteristics

Structure: rhombohedral Color: silvery white
Hardness:3.15 mohs
Harmful effects:

Like arsenic, which sits directly above it in the periodic table, the toxicity of antimony and its compounds varies according to the chemical state of the element. Many of the salts are carcinogenic.

The metallic form is considered to be less active whereas stibine (SbH3) and antimony trioxide are extremely toxic.(5) Antimony is toxic and immediately dangerous to life or health at 50 mg m-3 or above. (6)

Exposure to 9 milligrams per cubic meter of air (mg/m3) of antimony as stibnite for a long time can irritate your eyes, skin, and lungs. Breathing 2 mg/m3 of antimony for a long time can cause problems with the lungs (pneumoconiosis) heart problems (altered electrocardiograms), stomach pain, diarrhoea, vomiting and stomach ulcers. People who drank over 19 ppm of antimony once, vomited. (7)

Characteristics:

Antimony is metalloid, so it has some metallic properties but not enough to be classified as a true metal. Physically, it behaves like sulfur while chemically it is more metallic. (1)

Antimony's electrical and thermal conductivity are lower than most metals' conductivities.

Antimony is a brittle, fusible, crystalline solid. It is easily powdered.

Antimony also has the unusual property that (like water) it expands as it freezes. Four other elements expand when they freeze; silicon, bismuth, gallium and germanium. 

In addition to the usual form of antimony, there are two allotropes: yellow crystalline and amorphous black.


Uses:

The major use of antimony is in lead alloys - mainly for use in batteries - adding hardness and smoothness of finish. The higher the proportion of antimony in the alloy, the harder and more brittle it will be. Alloys made with antimony expand on cooling, retaining the finer details of molds. Antimony alloys are therefore used in making typefaces for clear, sharp printing.

Babbit metals, used for machinery bearings, are alloys of lead, tin, copper and antimony. These metals are hard but slippery and so ideal for use as bearings. (8)

Antimony is used in the semiconductor industry as an n-type dopant for silicon.

Antimony trioxide is used as a flame retardant in adhesives, plastics, rubber and textiles.

Reactions

Reaction with air:mild, w/ht, ⇒ Sb2Ox x=3-5 Reaction with 6 M HCl:none
Reaction with 15 M HNO3:mild, ⇒ Sb2O5 Reaction with 6 M NaOH:none

Compounds

Oxide(s):Sb2O3 Sb2O4 Sb2O5 Chloride(s):SbCl3 SbCl5
Hydride(s):SbH3

Radius

Atomic radius:140 pm Ionic radius (1+ ion):pm
Ionic radius (2+ ion):pm Ionic radius (3+ ion):90 pm
Ionic radius (2- ion):pm Ionic radius (1- ion):pm

Conductivity

Thermal conductivity:24.4 W m-1 K-1 Electrical conductivity: 25.641 x 106 S m-1

Abundance & Isotopes

Abundance earth's crust:0.2 parts per million by weight, 0.03 parts per million by moles
Abundance solar system:950 parts per billion by weight, 10 parts per trillion by moles
Cost, pure: $4.5 per 100g
Cost, bulk:$0.44 per 100g
Source:

Most antimony is produced from stibnite (antimony sulfide, Sb2S3). It is also extracted as a byproduct of copper, gold and silver production.

Isotopes:

31 whose half-lives are known, mass numbers 104 to 136. Of these, two are stable and found naturally in the percentages shown: 121Sb (57.36%) and 123Sb (42.64%).

Other

Other:

References
1. Robert E. Krebs, The history and use of our earth's chemical elements: a reference guide., (2006) p219. Greenwood Publishing Group
2. Thomas Thomson, The history of chemistry, Volume 1, (1830) p74. (ebook digitized by Google)
3. Vannoccio Biringuccio, The Pirotechnia of Vannoccio Biringuccio, translated by Cyril Stanley Smith and Martha Teach Gnudi, (1990) p201. Dover Publications
4. Mahadev M. Kumbar, Chemistry in a Day of Student's Life, (2003) p179. iUniverse
5. http://www.nrc-cnrc.gc.ca/eng/education/elements/el/sb.html
6. http://www.osha.gov/dts/chemicalsampling/data/CH_219100.html
7. http://www.atsdr.cdc.gov/toxprofiles/tp23.pdf
8. George Stuart Brady, Henry R. Clauser, John A. Vaccari Materials Handbook., (2002) p74. McGraw Hill Professional