Sulfur burns with a blue flame that emits sulfur dioxide , notable for its peculiar suffocating odor. Sulfur is insoluble in water but soluble in carbon disulfide and to a lesser extent in other non-polar organic solvents such as benzene and toluene. Sulfur forms stable compounds with all elements except the noble gases.
Sulfur in the solid state ordinarily exists as cyclic crown-shaped S 8 molecules. The crystallography of sulfur is complex. Depending on the specific conditions, the sulfur allotropes form several distinct crystal structures , with rhombic and monoclinic S 8 best known. The molten sulfur assumes a dark red color above this temperature. At higher temperatures, however, the viscosity is decreased as depolymerization occurs.
Amorphous or "plastic" sulfur can be produced through the rapid cooling of molten sulfur. X-ray crystallography studies show that the amorphous form may have a helical structure with eight atoms per turn.
This form is metastable at room temperature and gradually reverts back to crystalline form. This process happens within a matter of hours to days but can be rapidly catalyzed. Sulfur is extracted by mainly two processes: the Sicilian process and the Frasch process. The Sicilian process, which was first used in Sicily, was used in ancient times to get sulfur from rocks present in volcanic regions.
In this process, the sulfur deposits are piled and stacked in brick kilns built on sloping hillsides, and with airspaces between them. Then powdered sulfur is put on top of the sulfur deposit and ignited. As the sulfur burns, the heat melts the sulfur deposits, causing the molten sulfur to flow down the sloping hillside. The molten sulfur can then be collected in wooden buckets. The second process used to obtain sulfur is the Frasch process. In this method, three concentric pipes are used: the outermost pipe contains superheated water, which melts the sulfur, and the innermost pipe is filled with hot compressed air, which serves to create foam and pressure.
The resulting sulfur foam is then expelled through the middle pipe. The Frasch process produces sulfur with a The sulfur produced by the Sicilian process must be purified by distillation.
The Claus process is used to extract elemental sulfur from hydrogen sulfide produced in hydrodesulfurization of petroleum or from natural gas. Hydrogen sulfide has the characteristic smell of rotten eggs.
Dissolved in water, hydrogen sulfide is acidic and will react with metals to form a series of metal sulfides. Natural metal sulfides are common, especially those of iron. Iron sulfide is called pyrite , the so-called fool's gold. Pyrite can show semiconductor properties. Many of the unpleasant odors of organic matter are based on sulfur-containing compounds such as methyl and ethyl mercaptan , also used to scent natural gas so that leaks are easily detectable.
The odor of garlic and "skunk stink" are also caused by sulfur-containing organic compounds. Not all organic sulfur compounds smell unpleasant; for example, grapefruit mercaptan , a sulfur-containing monoterpenoid is responsible for the characteristic scent of grapefruit.
Polymeric sulfur nitride has metallic properties even though it does not contain any metal atoms. Even better, the process is so simple that Pyun and his colleagues call it "cave man chemistry.
The team has been approached by several companies interested in taking the sulfur polymerization process commercial. Which could be good news for the environment. Conventional oil and gas reservoirs are about 1 to 5 percent sulfur, Pyun said. More and more, however, oil and gas exploration is tapping into unconventional reservoirs filled with nastier stuff: The oil from tar sands in Alberta, Canada, is 20 percent sulfur.
Some new fields in the Middle East produce oil that is up to 40 percent sulfur, Pyun added. With any luck, his team's process can turn that garbage into something useful. Elemental sulfur is a commonly used pesticide on many American and European farms. It is approved for use on both conventional and organic crops to help control fungus and other pests. In California alone, more than 21 million kilograms Although the Environmental Protection Agency EPA has labeled elemental sulfur as generally safe, studies have shown that this type of pesticide is a respiratory irritant to farmworkers.
Now, a new study by researchers at the University of California, Berkeley, has gone a step further and looked at the respiratory health of residents living near treated fields — specifically, hundreds of children living in the agricultural community of Salinas Valley, California. Their findings were published in August in the journal Environmental Health Perspectives. The researchers found that children living within a half-mile from recent elemental sulfur applications had reduced lung function, higher levels of asthma-related symptoms and greater asthma medication use, compared to unexposed children.
Help text not available for this section currently. Elements and Periodic Table History. Sulfur is mentioned 15 times in the Bible , and was best known for destroying Sodom and Gomorrah. It was also known to the ancient Greeks, and burnt as a fumigant.
Sulfur was mined near Mount Etna in Sicily and used for bleaching cloth and preserving wine, both of which involved burning it to form sulfur dioxide, and allowing this to be absorbed by wet clothes or the grape juice.
For centuries, sulfur along with mercury and salt, was believed to be a component of all metals and formed the basis of alchemy whereby one metal could be transmuted into another. Antoine Lavoisier thought that sulfur was an element, but in Humphry Davy said it contained hydrogen. Atomic data. Bond enthalpies. Glossary Common oxidation states The oxidation state of an atom is a measure of the degree of oxidation of an atom.
Oxidation states and isotopes. Glossary Data for this section been provided by the British Geological Survey. Relative supply risk An integrated supply risk index from 1 very low risk to 10 very high risk. Recycling rate The percentage of a commodity which is recycled. Substitutability The availability of suitable substitutes for a given commodity. Reserve distribution The percentage of the world reserves located in the country with the largest reserves.
Political stability of top producer A percentile rank for the political stability of the top producing country, derived from World Bank governance indicators. Political stability of top reserve holder A percentile rank for the political stability of the country with the largest reserves, derived from World Bank governance indicators. Supply risk. Relative supply risk 3. Young's modulus A measure of the stiffness of a substance.
Shear modulus A measure of how difficult it is to deform a material. Bulk modulus A measure of how difficult it is to compress a substance. Vapour pressure A measure of the propensity of a substance to evaporate.
Pressure and temperature data — advanced. Listen to Sulfur Podcast Transcript :. You're listening to Chemistry in its element brought to you by Chemistry World , the magazine of the Royal Society of Chemistry. Hello, this week stinky sediments, skunks and the smell of hell. Well they all begin with the letter S, and so does this week's element.
Here's Steve Mylon. The smell of the sediment tells a great deal about the underlying chemistry. Thick black anoxic sediments can be accompanied by a putrid smell which is unique to reduced sulfur.
Maybe this is why sulfur has such a bad reputation. My son wouldn't eat eggs for 6 months when he got a smell of his first rotten one. In the bible it seems that whenever something bad happens or is about to happen burning sulfur is in the picture:. And in Revelation we read that the sinners will find their place in a fiery lake of burning sulfur. The odd thing is that in both cases we shouldn't expect anything smelly to be produced. When sulfur burns in air, it generally forms sulfur dioxide or sulfur trioxide, the latter of which lacks any smell [amended from the podcast audio file, which states that sulfur dioxide does not smell].
These compounds can further oxidize and rain out as sulfuric or sulfurous acid. This is the mechanism for acid rain which has reeked havoc on the forests of the northeastern United States as sulfur rich coals are burned to generate electricity in midwestern states and carried east by prevailing winds where sulfuric acid is rained out causing all sorts of ecological problems. Additionally, the combination of burning coal and fog creates smog in many industrial cities causing respiratory problems among the locals.
Here too, sulfur dioxide and sulfuric acid are implicated as the culprits. But again, there is no smell associated with this form of sulfur. But reduce sulfur by giving it a couple of electrons, and its smell is unmistakable. The requirement of sulfur reduction to sulfide has clearly been lost in translation. Hell that smells like hydrogen sulfide or any number of organic-sulfur compound will not be a nice place at all.
The organic sulfide compounds known as thiols or mercaptans smell so bad, that they are commonly added to odorless natural gas in very small quantities in order to serve as a 'smell alarm' should there be leak in a natural gas line. Skunks take advantage of the foul smell of butyl seleno-mercaptan as a means of defending themselves against their enemies.
And for me, personally, the worst chemistry of all occurs when reduced sulfur imparts a bad skunky taste in bottles of wine or beer. So, where does the "smell of hell" come from in anoxic sediments. Interestingly, some bacteria have evolved to make use of oxidized sulfur , sulfate, as an electron acceptor during respiration. In a similar manner to the way humans reduce elemental oxygen to water, these bacteria reduce sulfate to hydrogen sulfide- They clearly don't mind the smell. Smell is not the only interesting chemistry that accompanies reduced sulfur.
The deep black associated with anoxic sediments results from the low solubility of most metal sulfides. Sulfate reduction to sulfide generally accompanies the precipitation of pyrite iron sulfide , cinnabar mercury sulfide , galena lead sulfide and many more minerals.
These metal sulfides have become an important industrial source for many of these important metals. Industry is one place you are almost certain to find sulfur or more importantly sulfuric acid which is used in processes ranging from fertilizer production to oil refining.
In fact sulfuric acid ranks as the most highly produced chemical in the industrialized world. Imagine that, the element with such a hellish reputation has become one of the most important. And some even suggest that sulfur could save the planet. The biogenic compound dimethylsulfide DMS is produced from the cleavage of dimethylsufonoprioponate, an osmotic regulatory compound produced by plankton in the ocean.
DMS is oxidized to SO2 and finally to sulfuric acid particles which can act as cloud condensation nuclei forming clouds which have a net cooling effect to the planet. Imagine warmer temperatures followed by greater biological activity resulting in more DMS to the atmosphere. The resulting cloud formation might work to cool a warming planet.
It's almost like the plankton are opening an umbrella made up-in part- of sulfur. From a symbol of damnation to savior Sometime around , Antoine Lavoisier convinced the rest of the scientific community that sulfur was an element.
The majority of the sulfur produced today is obtained from underground deposits, usually found in conjunction with salt deposits, with a process known as the Frasch process. Sulfur is a pale yellow, odorless and brittle material.
It displays three allotropic forms: orthorhombic, monoclinic and amorphous. The orthorhombic form is the most stable form of sulfur. Amorphous sulfur is formed when molten sulfur is quickly cooled. Amorphous sulfur is soft and elastic and eventually reverts back to the orthorhombic form.
0コメント