Difference between revisions of "Antimony"
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| − | '''Antimony''' is a chemical element with symbol '''Sb''' (from Latin: ''stibium'', though in some countries it's called '''stibium''' or a variation of the word) and atomic number 51. It is a metalloid. | + | '''Antimony''' is a chemical element with symbol '''Sb''' (from Latin: ''stibium'', though in some countries it's called '''stibium''' or a variation of the word) and atomic number 51. It is a [[metalloid]]. |
==Properties== | ==Properties== | ||
Latest revision as of 12:19, 18 October 2019
 Antimony lump. | |||||
| General properties | |||||
|---|---|---|---|---|---|
| Name, symbol | Antimony, Sb | ||||
| Alternative name | Stibium | ||||
| Allotropes | Metallic, explosive, black, yellow | ||||
| Appearance | Silvery lustrous gray | ||||
| Antimony in the periodic table | |||||
| |||||
| Atomic number | 51 | ||||
| Standard atomic weight (Ar) | 121.760 | ||||
| Group, block | , p-block | ||||
| Period | period 5 | ||||
| Electron configuration | [Kr] 4d10 5s2 5p3 | ||||
per shell | 2, 8, 18, 18, 5 | ||||
| Physical properties | |||||
| Silvery-gray | |||||
| Phase | Solid | ||||
| Melting point | 903.78 K (630.63 °C, 1167.13 °F) | ||||
| Boiling point | 1908 K (1635 °C, 2975 °F) | ||||
| Density near r.t. | 6.697 g/cm3 | ||||
| when liquid, at | 6.53 g/cm3 | ||||
| Heat of fusion | 19.79 kJ/mol | ||||
| Heat of | 193.43 kJ/mol | ||||
| Molar heat capacity | 25.23 J/(mol·K) | ||||
| pressure | |||||
| Atomic properties | |||||
| Oxidation states | 5, 4, 3, 2, 1, −1, −2, −3 (an amphoteric oxide) | ||||
| Electronegativity | Pauling scale: 2.05 | ||||
| energies |
1st: 834 kJ/mol 2nd: 1594.9 kJ/mol 3rd: 2440 kJ/mol (more) | ||||
| Atomic radius | empirical: 140 pm | ||||
| Covalent radius | 139±5 pm | ||||
| Miscellanea | |||||
| Crystal structure | | ||||
| Speed of sound thin rod | 3420 m/s (at 20 °C) | ||||
| Thermal expansion | 11 µm/(m·K) | ||||
| Thermal conductivity | 24.4 W/(m·K) | ||||
| Electrical resistivity | 417 nΩ·m (at 20 °C) | ||||
| Magnetic ordering | Diamagnetic | ||||
| Young's modulus | 55 GPa | ||||
| Shear modulus | 20 GPa | ||||
| Bulk modulus | 42 GPa | ||||
| Mohs hardness | 3.0 | ||||
| Brinell hardness | 294–384 MPa | ||||
| CAS Registry Number | 7440-36-0 | ||||
| History | |||||
| Discovery | 3000 BC | ||||
| First isolation | Vannoccio Biringuccio (1540) | ||||
Antimony is a chemical element with symbol Sb (from Latin: stibium, though in some countries it's called stibium or a variation of the word) and atomic number 51. It is a metalloid.
Contents
Properties
Chemical
Antimony is stable in air at room temperature, but will burn in air to give antimony(III) oxide:
- 4 Sb + 3 O2 → 2 Sb2O3
Antimony pentoxide (Sb4O10) cannot form by burning the element in open air, and is obtained by oxidizing antimony with concentrated nitric acid. Antimony also forms a mixed-valence oxide, antimony tetroxide (Sb2O4), which features both Sb(III) and Sb(V). Unlike the oxides of phosphorus and arsenic, antimony oxides are amphoteric, and do not form well-defined oxoacids and react with acids to form antimony salts.
Antimony is resistant to attack by most acids.
Antimony forms two series of halides: SbX3 and SbX5.
The trihalides are formed by reacting antimony, antimony(III) oxide or antimony(III) sulfide with hydrohalic acids, in inert conditions. The presence of moisture leads to hydrolysis. The pentahalides are formed by oxidizing the trihalides with their respective halogen.
Organoantimony compounds are typically prepared by alkylation of antimony halides with Grignard reagents, in an aprotic solvent. A large variety of compounds are known with both Sb(III) and Sb(V) centers, including mixed halo-organic derivatives, anions, and cations. Examples include triphenylstibine Sb(C6H5)3, chlorodiphenylstibine Sb(C6H5)2Cl, etc. Pentacoordinated organoantimony compounds are common, examples being Sb(C6H5)5 and several related halides.
Physical
Antimony is a silvery gray metalloid. It has several allotrope forms:
- Metallic: The most stable form of antimony. It has the aspect of a brittle, silver-white solid. It melts at 630.63 °C and boils at 1635 °C. It has a density of 6.697 g/cm3.
- Black: Formed upon rapid cooling of metallic antimony vapors. It has the same crystal structure as red phosphorus and black arsenic, but is much more reactive. It oxidizes in air and may ignite spontaneously. At 100 °C, black antimony gradually transforms into the stable metallic form.
- Explosive: can be made via electrolysis of antimony(III) chloride. If scratched with a sharp object, an exothermic reaction occurs and white fumes are given off as metallic antimony is formed. Can detonate if grounded with a pestle in a mortar.
- Yellow: The most unstable allotrope form. Can only be made by oxidation of stibine (SbH3) at −90 °C. Above this temperature and in ambient light, this metastable allotrope transforms into the more stable black allotrope.
Availability
Antimony is sold by various chemical suppliers and can also be found on eBay and Amazon.
It can also be found in certain solders, as an alloy with tin.
Free antimony occurs in a few mines around the world.
Isolation
Antimony can be extracted by reducing it's ore, stibnite (Sb2S3) with a reducing agent, such as iron. Carbon can also be used.
Projects
- Make antimony halides
- Make antimony alloys
- Make explosive antimony
- Element collecting
Handling
Safety
Antimony does not affect human and environmental health significantly. Inhalation of antimony trioxide (and similar poorly soluble Sb(III) dust particles such as antimony dust) is however considered harmful and suspected of causing cancer. Prolonged skin contact with antimony dust may cause dermatitis. Certain organometallic compounds of antimony may cause blisters on contact with unprotected skin.
Storage
Antimony should be stored in closed bottles, away from corrosive chemicals.
Disposal
Antimony is best recycled. Antimony compounds should be reduced to antimony element or oxide and either recycled or taken to disposal centers.
