Sulfur Facts

Sulfur Chemical & Physical Properties

Crystals of the nonmetallic element sulfur.
Crystals of the nonmetallic element sulfur. Smithsonian Institution

Sulfur Basic Facts

Atomic Number: 16

Symbol: S

Atomic Weight: 32.066

Discovery: Known since prehistoric time.

Electron Configuration: [Ne] 3s2 3p4

Word Origin: Sanskrit: sulvere, Latin: sulpur, sulphurium: words for sulfur or brimstone

Isotopes: Sulfur has 21 known isotopes ranging from S-27 to S-46 and S-48. Four isotopes are stable: S-32, S-33, S-34 and S-36. S-32 is the most common isotope with an abundance of 95.02%.

Properties: Sulfur has a melting point of 112.8°C (rhombic) or 119.0°C (monoclinic), boiling point of 444.674°C, specific gravity of 2.07 (rhombic) or 1.957 (monoclinic) at 20°C, with a valence of 2, 4, or 6. Sulfur is a pale yellow, brittle, odorless solid. It is insoluble in water, but soluble in carbon disulfide. Multiple allotropes of sulfur are known.

Uses: Sulfur is a component of gunpowder. It is used in the vulcanization of rubber. Sulfur has applications as a fungicide, fumigant, and in the making of fertilizers. It is used to make sulfuric acid. Sulfur is used in the making of several types of paper and as a bleaching agent. Elemental sulfur is used as an electrical insulator. The organic compounds of sulfur have many uses. Sulfur is an element that is essential for life. However, sulfur compounds can be highly toxic. For example, small amounts of hydrogen sulfide can be metabolized, but higher concentrations can quickly cause death from respiratory paralysis.

Hydrogen sulfide quickly deadens the sense of smell. Sulfur dioxide is an important atmospheric pollutant.

Sources: Sulfur is found in meteorites and native in proximity to hot springs and volcanoes. It is found in many minerals, including galena, iron pyrite, sphalerite, stibnite, cinnabar, Epsom salts, gypsum, celestite, and barite.

Sulfur also occurs in petroleum crude oil and natural gas. The Frasch process may be used to obtain sulfur commercially. In this process, heated water is forced into wells sunk into salt domes in order to melt the sulfur. The water is then brought to the surface.

Element Classification: Non-Metal

Sulfur Physical Data

Density (g/cc): 2.070

Melting Point (K): 386

Boiling Point (K): 717.824

Appearance: tasteless, odorless, yellow, brittle solid

Atomic Radius (pm): 127

Atomic Volume (cc/mol): 15.5

Covalent Radius (pm): 102

Ionic Radius: 30 (+6e) 184 (-2e)

Specific Heat (@20°C J/g mol): 0.732

Fusion Heat (kJ/mol): 1.23

Evaporation Heat (kJ/mol): 10.5

Pauling Negativity Number: 2.58

First Ionizing Energy (kJ/mol): 999.0

Oxidation States: 6, 4, 2, -2

Lattice Structure: Orthorhombic

Lattice Constant (Å): 10.470

CAS Registry Number: 7704-34-9

Sulfur Trivia:

  • Pure sulfur has no smell. The strong smell associated with sulfur should actually be attributed to compounds of sulfur.
  • Brimstone is an ancient name for sulfur that means "burning stone".
  • Molten sulfur is red.
  • Sulfur burns with a blue flame in a flame test.
  • Sulfur is the seventeenth most common element in the Earth's crust.
  • Sulfur is the eighth most common element in the human body.
  • Sulfur is the sixth most common element in seawater.
  • Gunpowder contains sulfur, carbon and saltpeter.

Sulfur or Sulphur?: The 'f' spelling of sulfur was originally introduced in the United States in the 1828 Webster dictionary. Other English texts kept the 'ph' spelling. The IUPAC formally adopted the 'f' spelling in 1990.

References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952), CRC Handbook of Chemistry & Physics (18th Ed.) International Atomic Energy Agency ENSDF database (Oct 2010)

Quiz: Ready to test your sulfur facts knowledge? Take the Sulfur Facts Quiz.

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