background information about sulphur
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| General | |||||||||||||||||||||||||||||||||||||
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| Name, symbol, number | sulfur, S, 16 | ||||||||||||||||||||||||||||||||||||
| Chemical series | nonmetals | ||||||||||||||||||||||||||||||||||||
| Group, period, block | 16, 3, p | ||||||||||||||||||||||||||||||||||||
| Appearance | Lemon yellow crystals. | ||||||||||||||||||||||||||||||||||||
| Standard atomic weight | 32.065 (5) g·mol−1 | ||||||||||||||||||||||||||||||||||||
| Electron configuration | [Ne] 3s2 3p4 | ||||||||||||||||||||||||||||||||||||
| Electrons per shell | 2, 8, 6 | ||||||||||||||||||||||||||||||||||||
| Physical properties | |||||||||||||||||||||||||||||||||||||
| Phase | solid | ||||||||||||||||||||||||||||||||||||
| Density (near r.t.) | (alpha) 2.07 g·cm−3 | ||||||||||||||||||||||||||||||||||||
| Density (near r.t.) | (beta) 1.96 g·cm−3 | ||||||||||||||||||||||||||||||||||||
| Density (near r.t.) | (gamma) 1.92 g·cm−3 | ||||||||||||||||||||||||||||||||||||
| Liquid density at m.p. | 1.819 g·cm−3 | ||||||||||||||||||||||||||||||||||||
| Melting point | 38.36 K (115.21 ° C, 239.38 ° F) | ||||||||||||||||||||||||||||||||||||
| Boiling point | 717.8 K (444.6 ° C, 832.3 ° F) | ||||||||||||||||||||||||||||||||||||
| Critical point | 1314 K, 20.7 MPa | ||||||||||||||||||||||||||||||||||||
| Heat of fusion | (mono) 1.727 kJ·mol−1 | ||||||||||||||||||||||||||||||||||||
| Heat of vaporization | (mono) 45 kJ·mol−1 | ||||||||||||||||||||||||||||||||||||
| Heat capacity | (25 °C) 22.75 J·mol−1·K−1 | ||||||||||||||||||||||||||||||||||||
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| Atomic properties | |||||||||||||||||||||||||||||||||||||
| Crystal structure | orthorhombic | ||||||||||||||||||||||||||||||||||||
| Oxidation states | 6, 4, 2, 1 [1], -2 (strongly acidic oxide) | ||||||||||||||||||||||||||||||||||||
| Electronegativity | 2.58 (Pauling scale) | ||||||||||||||||||||||||||||||||||||
| Ionization energies ( more) | 1st: 999.6 kJ·mol−1 | ||||||||||||||||||||||||||||||||||||
| 2nd: 2252 kJ·mol−1 | |||||||||||||||||||||||||||||||||||||
| 3rd: 3357 kJ·mol−1 | |||||||||||||||||||||||||||||||||||||
| Atomic radius | 100 pm | ||||||||||||||||||||||||||||||||||||
| Atomic radius (calc.) | 88 pm | ||||||||||||||||||||||||||||||||||||
| Covalent radius | 102 pm | ||||||||||||||||||||||||||||||||||||
| Van der Waals radius | 180 pm | ||||||||||||||||||||||||||||||||||||
| Miscellaneous | |||||||||||||||||||||||||||||||||||||
| Magnetic ordering | no data | ||||||||||||||||||||||||||||||||||||
| Electrical resistivity | (20 °C) (amorphous) 2×1015Ω·m | ||||||||||||||||||||||||||||||||||||
| Thermal conductivity | (300 K) (amorphous) 0.205 W·m−1·K−1 | ||||||||||||||||||||||||||||||||||||
| Bulk modulus | 7.7 GPa | ||||||||||||||||||||||||||||||||||||
| Mohs hardness | 2.0 | ||||||||||||||||||||||||||||||||||||
| CAS registry number | 7704-34-9 | ||||||||||||||||||||||||||||||||||||
| Selected isotopes | |||||||||||||||||||||||||||||||||||||
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| References | |||||||||||||||||||||||||||||||||||||
Sulfur or sulphur is the chemical element that has the symbol S and atomic number 16. It is an abundant, tasteless, multivalent non-metal. Sulfur, in its native form, is a yellow crystalline solid. In nature, it can be found as the pure element or as sulfide and sulfate minerals. It is an essential element for life and is found in two amino acids, cysteine and methionine. Its commercial uses are primarily in fertilizers, but it is also widely used in gunpowder, matches, insecticides and fungicides. Elemental sulfur crystals are commonly sought after by mineral collectors for their brightly colored polyhedron shapes.
Contents[ hide] |
History
Sulfur ( Sanskrit, sulvari; Latin sulfur or sulpur) was known in ancient times, and is referred to in the Biblical Pentateuch (Genesis).
English translations of the Bible commonly refered to sulfur as "brimstone", giving rise to the name of ' Fire and brimstone' sermons, in which listeners are reminded of the fate of eternal damnation that awaits the unbelieving and unrepentant. It is from this part of the Bible that Hell is implied to "smell of sulfur", although as mentioned above sulfur is in fact odorless. The "smell of sulfur" usually refers to either the odor of hydrogen sulfide, e.g. from rotten eggs, or of burning sulfur, which produces sulfur dioxide, the smell associated with burnt matches.
Sulfur was known in China since the 6th century BC, in a natural form that the Chinese had called 'brimstone', or shiliuhuang that was found in Hanzhong. [1] By the 3rd century, the Chinese discovered that sulfur could be extracted from pyrite. [1] Chinese Daoists were interested in sulfur's flammability and its reactivity with certain metals, yet its earliest practical uses were found in traditional Chinese medicine. [1] A Song Dynasty military treatise of 1044 AD described different formulas for Chinese gun powder, which is a mixture of potassium nitrate ( K N O3), carbon, and sulfur. Early alchemists gave sulfur its own alchemical symbol which was a triangle at the top of a cross.
In the late 1770s, Antoine Lavoisier helped convince the scientific community that sulfur was an element and not a compound. In 1867, sulfur was discovered in underground deposits in Louisiana and Texas. The overlying layer of earth was quicksand, prohibiting ordinary mining operations, therefore the Frasch process was used.
Spelling
The element has traditionally been spelled sulphur in the United Kingdom, Ireland, Hong Kong, the Commonwealth Caribbean and India, but sulfur in the United States, while both spellings are used in Australia, New Zealand and Canada. IUPAC adopted the spelling “sulfur” in 1990, as did the Royal Society of Chemistry Nomenclature Committee in 1992 [2] and the Qualifications and Curriculum Authority for England and Wales recommended its use in 2000. [3] The spelling of the term in non-official texts is gradually becoming uniform as sulfur.
In Latin, the word is variously written sulpur, sulphur, and sulfur (the Oxford Latin Dictionary lists the spellings in this order). It is an original Latin name and not a Classical Greek loan, so the ph variant does not denote the Greek letter φ. Sulfur in Greek is theion (θεῖον), whence comes the prefix thio-. The simplification of the Latin word's p or ph to an f appears to have taken place towards the end of the classical period, with the f spelling becoming dominant in the medieval period. [4]
Isotopes
Sulfur has 18 isotopes, four of which are stable: 32S (95.02%), 33S (0.75%), 34S (4.21%), and 36S (0.02%). Other than 35S, the radioactive isotopes of sulfur are all short lived. 35S is formed from cosmic ray spallation of 40 argon in the atmosphere It has a half-life of 87 days.
When sulfide minerals are precipitated, isotopic equilibration among solids and liquid may cause small differences in the δS-34 values of co-genetic minerals. The differences between minerals can be used to estimate the temperature of equilibration. The δ C-13 and δS-34 of coexisting carbonates and sulfides can be used to determine the pH and oxygen fugacity of the ore-bearing fluid during ore formation.
In most forest ecosystems, sulfate is derived mostly from the atmosphere; weathering of ore minerals and evaporites also contribute some sulfur. Sulfur with a distinctive isotopic composition has been used to identify pollution sources, and enriched sulfur has been added as a tracer in hydrologic studies. Differences in the natural abundances can also be used in systems where there is sufficient variation in the 34S of ecosystem components. Rocky Mountain lakes thought to be dominated by atmospheric sources of sulfate have been found to have different δS-34 values from lakes believed to be dominated by watershed sources of sulfate.
Allotropes
Sulfur forms more than 30 solid allotropes, more than than any other element. [5] Besides S8, several other rings are known. [6] Removing one atom from the crown gives S7, which is more deeply yellow than S8. HPLC analysis of "elemental sulfur" reveals an equilibrium mixture of mainly S8, but also S7 and small amounts of S6. [7] Larger rings have been prepared, including S12 and S18. [8] [9] By contrast, sulfur's lighter neighbor oxygen only exists in two states of allotropic significance: O2 and O3. Selenium, the heavier analogue of sulfur can form rings but is more often found as a polymer chain.
Occurrence
Elemental sulfur can be found near hot springs and volcanic regions in many parts of the world, especially along the Pacific Ring of Fire. Such volcanic deposits are currently mined in Indonesia, Chile, and Japan. Sicily is also famous for its sulfur mines.
Significant deposits of elemental sulfur also exist in salt domes along the coast of the Gulf of Mexico, and in evaporites in eastern Europe and western Asia. The sulfur in these deposits is believed to come from the action of anaerobic bacteria on sulfate minerals, especially gypsum, although apparently native sulfur may be produced by geological processes alone, without the aid of living organisms (see below). However, fossil-based sulfur deposits from salt domes are the basis for commercial production in the United States, Poland, Russia, Turkmenistan, and Ukraine.
Sulfur production through hydrodesulfurization of oil, gas, and the Athabasca Oil Sands has produced a surplus - huge stockpiles of sulfur now exist throughout Alberta, Canada.
Common naturally occurring sulfur compounds include the sulfide minerals, such as pyrite (iron sulfide), cinnabar (mercury sulfide), galena (lead sulfide), sphalerite (zinc sulfide) and stibnite (antimony sulfide); and the sulfates, such as gypsum (calcium sulfate), alunite (potassium aluminium sulfate), and barite (barium sulfate). It occurs naturally in volcanic emissions, such as from hydrothermal vents, and from bacterial action on decaying sulfur-containing organic matter.
The distinctive colors of Jupiter's volcanic moon, Io, are from various forms of molten, solid and gaseous sulfur. There is also a dark area near the Lunar crater Aristarchus that may be a sulfur deposit.
Sulfur is present in many types of meteorites. Ordinary chondrites contain on average 2.1% sulfur, and carbonaceous chondrites may contain as much as 6.6%. Sulfur in meteorites is normally present entirely as troilite (FeS), but other sulfides are found in some meteorites, and carbonaceous chondrites contain free sulfur, sulfates, and possibly other sulfur compounds. [10]
(see more about sulphur at the end of the newsletter)
Our deliveries are in lots of 20,000 - 30,000 MT.
Specifications:
ASH CONTENT (WT %) MAX.0.05
MOISTURE (WT %) MAX.0.50
ORGANIC (WT %) MAX. 0.05
ACIDITY (WT %) MAX. 0.02
COLOR BRIGHT YELLOW
Conditions: Buyers to submit formal LOI. Buyers DLC must then be issued in favor of seller no later than 10 days after signing of contract. The indicative price for our next cargo is USD440 PMT CFR North China main port or South African main port. FOB quotes also available, please inquire. Price valid until Dec 25, 2007.
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