Type: Lesser Element
Periodic Element: (S)
RDA: Not established; diet adequate in proteins meets body’s needs. Daily requirement estimated at about 1.2 g.
Importance- To Body:
Component of proteins, particularly muscle proteins. Structurally essential constituent of many proteins as amino acids are made into proteins: (insulin), many vitamins (thiamin and biotin: found in mucopolysaccharides present in cartilage, tendons, bone.
Distribution- In Body:
0.3 Approx. % of Body Mass
Widely distributed: particularly abundant in hair, skin, nails; excreted in urine.
Excess Effects:
None listed, not known
Deficiency Effects:
None listed, not known
Sources Food:
All protein containing foods; Meat, Milk, Eggs, Legumes (all rich in sulfur-containing amino acids)
Sources Environmental/Geographic:
None listed
Supplemental information:
General properties | |||||||||||||||||||||||||||||||
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Alternative name | sulphur (British spelling) | ||||||||||||||||||||||||||||||
Appearance | lemon yellow sintered microcrystals | ||||||||||||||||||||||||||||||
Standard atomic weight (Ar, standard) | [, 32.059] conventional: 32.076 32.06 | ||||||||||||||||||||||||||||||
Sulfur in the periodic table | |||||||||||||||||||||||||||||||
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Atomic number (Z) | 16 | ||||||||||||||||||||||||||||||
Group | group 16 (chalcogens) | ||||||||||||||||||||||||||||||
Period | period 3 | ||||||||||||||||||||||||||||||
Element category | polyatomic nonmetal | ||||||||||||||||||||||||||||||
Block | p-block | ||||||||||||||||||||||||||||||
Electron configuration | [Ne] 3s2 3p4 | ||||||||||||||||||||||||||||||
Electrons per shell
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2, 8, 6 | ||||||||||||||||||||||||||||||
Physical properties | |||||||||||||||||||||||||||||||
Phase at STP | solid | ||||||||||||||||||||||||||||||
Melting point | 388.36 K (115.21 °C, 239.38 °F) | ||||||||||||||||||||||||||||||
Boiling point | 717.8 K (444.6 °C, 832.3 °F) | ||||||||||||||||||||||||||||||
Density (near r.t.) | alpha: 2.07 g/cm3 beta: 1.96 g/cm3 gamma: 1.92 g/cm3 |
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when liquid (at m.p.) | 1.819 g/cm3 | ||||||||||||||||||||||||||||||
Critical point | 1314 K, 20.7 MPa | ||||||||||||||||||||||||||||||
Heat of fusion | mono: 1.727 kJ/mol | ||||||||||||||||||||||||||||||
Heat of vaporization | mono: 45 kJ/mol | ||||||||||||||||||||||||||||||
Molar heat capacity | 22.75 J/(mol·K) | ||||||||||||||||||||||||||||||
Vapor pressure
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Atomic properties | |||||||||||||||||||||||||||||||
Oxidation states | 6, 5, 4, 3, 2, 1, −1, −2 |
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Electronegativity | Pauling scale: 2.58 | ||||||||||||||||||||||||||||||
Ionization energies |
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Covalent radius | 105±3 pm | ||||||||||||||||||||||||||||||
Van der Waals radius | 180 pm | ||||||||||||||||||||||||||||||
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Miscellanea | |||||||||||||||||||||||||||||||
Crystal structure | orthorhombic | ||||||||||||||||||||||||||||||
Thermal conductivity | 0.205 W/(m·K) (amorphous) | ||||||||||||||||||||||||||||||
Electrical resistivity | 2×1015 Ω·m (at 20 °C) (amorphous) | ||||||||||||||||||||||||||||||
Magnetic ordering | diamagnetic | ||||||||||||||||||||||||||||||
Magnetic susceptibility | (α) −15.5·10−6 cm3/mol (298 K) | ||||||||||||||||||||||||||||||
Bulk modulus | 7.7 GPa | ||||||||||||||||||||||||||||||
Mohs hardness | 2.0 | ||||||||||||||||||||||||||||||
CAS Number | 7704-34-9 | ||||||||||||||||||||||||||||||
History | |||||||||||||||||||||||||||||||
Discovery | Chinese(before 2000 BCE) | ||||||||||||||||||||||||||||||
Recognized as an element by | Antoine Lavoisier (1777) | ||||||||||||||||||||||||||||||
Main isotopes of sulfur | |||||||||||||||||||||||||||||||
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Sulfur is a chemical element with symbol S and atomic number 16. It is abundant, multivalent, and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula S8. Elemental sulfur is a bright yellow crystalline solid at room temperature. Chemically, sulfur reacts with all elements except for gold, platinum, iridium, tellurium, and the noble gases.
Sulfur is the tenth most common element by mass in the universe, and the fifth most common on Earth. Though sometimes found in pure, native form, sulfur on Earth usually occurs as sulfide and sulfate minerals. Being abundant in native form, sulfur was known in ancient times, being mentioned for its uses in ancient India, ancient Greece, China, and Egypt. In the Bible, sulfur is called brimstone. Today, almost all elemental sulfur is produced as a byproduct of removing sulfur-containing contaminants from natural gas and petroleum. The greatest commercial use of the element is the production of sulfuric acid for sulfate and phosphate fertilizers, and other chemical processes. The element sulfur is used in matches, insecticides, and fungicides. Many sulfur compounds are odoriferous, and the smells of odorized natural gas, skunk scent, grapefruit, and garlic are due to organosulfur compounds. Hydrogen sulfide gives the characteristic odor to rotting eggs and other biological processes.
Sulfur is an essential element for all life, but almost always in the form of organosulfur compounds or metal sulfides. Three amino acids (cysteine, cystine, and methionine) and two vitamins (biotin and thiamine) are organosulfur compounds. Many cofactors also contain sulfur including glutathione and thioredoxin and iron–sulfur proteins. Disulfides, S–S bonds, confer mechanical strength and insolubility of the protein keratin, found in outer skin, hair, and feathers. Sulfur is one of the core chemical elements needed for biochemical functioning and is an elemental macronutrient for all living organisms.