General properties | |||||||||||||||||||||
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Pronunciation | |||||||||||||||||||||
Appearance | silvery lustrous gray | ||||||||||||||||||||
Standard atomic weight (Ar, standard) | 121.760(1) | ||||||||||||||||||||
Antimony in the periodic table | |||||||||||||||||||||
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Atomic number (Z) | 51 | ||||||||||||||||||||
Group | group 15 (pnictogens) | ||||||||||||||||||||
Period | period 5 | ||||||||||||||||||||
Element category | metalloid | ||||||||||||||||||||
Block | p-block | ||||||||||||||||||||
Electron configuration | [Kr] 4d10 5s2 5p3 | ||||||||||||||||||||
Electrons per shell
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2, 8, 18, 18, 5 | ||||||||||||||||||||
Physical properties | |||||||||||||||||||||
Phase at STP | 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 m.p.) | 6.53 g/cm3 | ||||||||||||||||||||
Heat of fusion | 19.79 kJ/mol | ||||||||||||||||||||
Heat of vaporization | 193.43 kJ/mol | ||||||||||||||||||||
Molar heat capacity | 25.23 J/(mol·K) | ||||||||||||||||||||
Vapor pressure
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Atomic properties | |||||||||||||||||||||
Oxidation states |
5, 4, 3, 2, 1, −1, −2, −3 |
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Electronegativity | Pauling scale: 2.05 | ||||||||||||||||||||
Ionization energies |
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Atomic radius | empirical: 140 pm | ||||||||||||||||||||
Covalent radius | 139±5 pm | ||||||||||||||||||||
Van der Waals radius | 206 pm | ||||||||||||||||||||
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Miscellanea | |||||||||||||||||||||
Crystal structure | rhombohedral | ||||||||||||||||||||
Speed of sound thin rod | 3420 m/s (at 20 °C) | ||||||||||||||||||||
Thermal expansion | 11 µm/(m·K) (at 25 °C) | ||||||||||||||||||||
Thermal conductivity | 24.4 W/(m·K) | ||||||||||||||||||||
Electrical resistivity | 417 nΩ·m (at 20 °C) | ||||||||||||||||||||
Magnetic ordering | diamagnetic | ||||||||||||||||||||
Magnetic susceptibility | −99.0·10−6 cm3/mol | ||||||||||||||||||||
Young's modulus | 55 GPa | ||||||||||||||||||||
Shear modulus | 20 GPa | ||||||||||||||||||||
Bulk modulus | 42 GPa | ||||||||||||||||||||
Mohs hardness | 3.0 | ||||||||||||||||||||
Brinell hardness | 294–384 MPa | ||||||||||||||||||||
CAS Number | 7440-36-0 | ||||||||||||||||||||
History | |||||||||||||||||||||
Discovery | ca. 800 | ||||||||||||||||||||
Main isotopes of antimony | |||||||||||||||||||||
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Antimony is a chemical element with symbol Sb (from Latin: stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient times and were powdered for use as medicine and cosmetics, often known by the Arabic name, kohl. Metallic antimony was also known, but it was erroneously identified as lead upon its discovery. The earliest known description of the metal in the West was written in 1540 by Vannoccio Biringuccio.
For some time, China has been the largest producer of antimony and its compounds, with most production coming from the Xikuangshan Mine in Hunan. The industrial methods for refining antimony are roasting and reduction with carbon or direct reduction of stibnite with iron.
The largest applications for metallic antimony is an alloy with lead and tin and the lead antimony plates in lead–acid batteries. Alloys of lead and tin with antimony have improved properties for solders, bullets, and plain bearings. Antimony compounds are prominent additives for chlorine and bromine-containing fire retardants found in many commercial and domestic products. An emerging application is the use of antimony in microelectronics.
Antimony is in a pnictogen (a member of group 15) and has an electronegativity of 2.05. In accordance with periodic trends, it is more electronegative than tin or bismuth, and less electronegative than tellurium or arsenic. Antimony is stable in air at room temperature, but reacts with oxygen if heated to produce antimony trioxide, Sb2O3.