Editing Sulfur (section)

==Applications==

===Sulfuric acid===
Elemental sulfur is used mainly as a precursor to other chemicals. Approximately 85% (1989) is converted to [[sulfuric acid]] (H<sub>2</sub>SO<sub>4</sub>):

{{block indent|{{frac|1|8}} {{chem2|S8}} + {{frac|3|2}} {{chem2|O2}} + {{chem2|H2O}} → {{chem2|H2SO4}}}}

[[File:Sulfuric acid 2000.png|thumb|upright=1.35|Sulfuric acid production in 2000]]
In 2010, the United States produced more sulfuric acid than any other inorganic industrial chemical.<ref name="Apodaca-2010">{{cite web|title= Mineral Yearbook 2010: Sulfur|author=Apodaca, Lori E. |publisher= United States Geological Survey|url= https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/mineral-pubs/sulfur/myb1-2010-sulfu.pdf}}</ref> The principal use for the acid is the extraction of phosphate ores for the production of fertilizer manufacturing. Other applications of sulfuric acid include oil refining, wastewater processing, and mineral extraction.<ref name="Nehb-2006" />

===Other important sulfur chemistry===
Sulfur reacts directly with methane to give [[carbon disulfide]], which is used to manufacture [[cellophane]] and [[rayon]].<ref name="Nehb-2006">{{cite book |last1=Nehb |first1=Wolfgang|last2=Vydra|first2=Karel |title=Ullmann's Encyclopedia of Industrial Chemistry |date=2006|publisher=Wiley-VCH Verlag|doi=10.1002/14356007.a25_507.pub2 |chapter=Sulfur |isbn=978-3-527-30673-2}}</ref> One of the uses of elemental sulfur is in [[vulcanization]] of rubber, where [[polysulfide]] chains crosslink organic polymers.<!--need something on pulping--> Large quantities of [[sulfite]]s are used to [[bleach (chemical)|bleach]] [[paper]] and to preserve [[dried fruit]]. Many [[surfactant]]s and [[detergent]]s (e.g. [[sodium lauryl sulfate]]) are sulfate derivatives. [[Calcium sulfate]], gypsum (CaSO<sub>4</sub>·2H<sub>2</sub>O) is mined on the scale of 100&nbsp;million [[tonne]]s each year for use in [[Portland cement]] and fertilizers.

When silver-based [[photography]] was widespread, sodium and ammonium [[sodium thiosulfate|thiosulfate]] were widely used as "fixing agents". Sulfur is a component of [[gunpowder]] ("black powder").

===Fertilizer===
[[Amino acid]]s synthesized by [[Organism|living organisms]] such as [[methionine]] and [[cysteine]] contain [[Organosulfur compounds|organosulfur]] groups ([[thioester]] and [[thiol]] respectively). The [[antioxidant]] [[glutathione]] protecting many living organisms against [[free radical]]s and [[oxidative stress]] also contains organic sulfur. Some [[crop]]s such as [[onion]] and [[garlic]] also produce different [[organosulfur compounds]] such as [[syn-Propanethial-S-oxide|''syn''-propanethial-''S''-oxide]] responsible of lacrymal irritation (onions), or [[diallyl disulfide]] and [[allicin]] (garlic). [[Sulfate]]s, commonly found in [[soil]]s and [[groundwater]]s are often a sufficient natural source of sulfur for plants and bacteria. [[Deposition (aerosol physics)|Atmospheric deposition]] of [[sulfur dioxide]] (SO<sub>2</sub>) is also a common artificial source ([[Coal combustion products|coal combustion]]) of sulfur for the soils. Under normal circumstances, in most agricultural soils, sulfur is not a [[Limiting factor|limiting nutrient]] for plants and [[microorganism]]s (see [[Liebig's law of the minimum#Liebig's barrel|Liebig's barrel]]). However, in some circumstances, soils can be depleted in [[sulfate]], e.g. if this later is leached by [[meteoric water]] ([[rain]]) or if the requirements in sulfur for some types of crops are high. This explains that sulfur is increasingly recognized and used as a component of [[fertilizer]]s. The most important form of sulfur for fertilizer is [[calcium sulfate]], commonly found in nature as the mineral [[gypsum]] (CaSO<sub>4</sub>·2H<sub>2</sub>O). Elemental sulfur is [[hydrophobic]] (not soluble in water) and cannot be used directly by plants. Elemental sulfur (ES) is sometimes mixed with [[bentonite]] to amend depleted soils for crops with high requirement in organo-sulfur. Over time, [[Redox|oxidation]] [[Abiotic component|abiotic]] processes with [[Earth atmosphere|atmospheric]] [[oxygen]] and [[Soil microbiology|soil bacteria]] can [[Redox|oxidize]] and convert elemental sulfur to soluble derivatives, which can then be used by microorganisms and plants. Sulfur improves the efficiency of other essential plant nutrients, particularly [[Nitrate|nitrogen]] and phosphorus.<ref name="sulphurinstitute-2020">{{Cite web |url=https://www.sulphurinstitute.org/about-sulphur/faq/#plants |title=FAQ – The Sulphur Institute |date=2020 |website=sulphurinstitute.org |publisher=[[The Sulphur Institute]] |access-date=27 February 2020}}</ref> Biologically produced sulfur particles are naturally [[Hydrophile|hydrophilic]] due to a [[biopolymer]] coating and are easier to disperse over the land in a spray of diluted slurry, resulting in a faster uptake by plants.

The plants requirement for sulfur equals or exceeds the requirement for [[phosphorus]]. It is an [[plant nutrition|essential nutrient for plant]] growth, [[root nodule]] formation of legumes, and immunity and defense systems. Sulfur deficiency has become widespread in many countries in Europe.<ref>{{cite journal|doi= 10.1006/jcrs.1998.0241|title= Sulphur Assimilation and Effects on Yield and Quality of Wheat|date= 1999|last1= Zhao|first1= F.|journal= Journal of Cereal Science|volume= 30|issue= 1|pages= 1–17|last2= Hawkesford|first2= M. J.|last3= McGrath|first3= S. P.}}</ref><ref>{{cite journal|title= Diagnosing sulfur deficiency in field-grown oilseed rape (Brassica napus L.) and wheat (Triticum aestivum L.)|doi= 10.1023/A:1026503812267|date= 2000|last1= Blake-Kalff|first1= M. M. A.|journal= Plant and Soil|volume= 225|issue= 1/2|pages= 95–107|bibcode= 2000PlSoi.225...95B|s2cid= 44208638}}</ref><ref>{{cite journal|doi= 10.1007/BF00747690|title= Plant nutrient sulphur-a review of nutrient balance, environmental impact and fertilizers|date= 1996|last1= Ceccotti|first1= S. P.|journal= Fertilizer Research|volume= 43|issue= 1–3|pages= 117–125|s2cid= 42207099}}</ref> Because atmospheric inputs of sulfur continue to decrease, the deficit in the sulfur input/output is likely to increase unless sulfur fertilizers are used. Atmospheric inputs of sulfur decrease because of actions taken to limit [[acid rain]]s.<ref name="NASA-2011">{{Citation|title=Glossary |at=acid rain |publisher=[[NASA Earth Observatory]] |location=United States |url=http://earthobservatory.nasa.gov/Glossary/?mode=all |access-date=February 15, 2013 |archive-url=https://web.archive.org/web/20111213175357/http://earthobservatory.nasa.gov/Glossary/?mode=all |archive-date=December 13, 2011 |url-status=live }}</ref><ref name="sulphurinstitute-2020" />

===Fungicide and pesticide===<!--[[Wettable Sulfur]] redirs here-->
[[File:Sulphur Candle.jpg|thumb|upright=0.8|Sulfur candle originally sold for home fumigation]]
Elemental sulfur is one of the oldest fungicides and [[pesticide]]s. "Dusting sulfur", elemental sulfur in powdered form, is a common fungicide for grapes, strawberry, many vegetables and several other crops. It has a good efficacy against a wide range of [[powdery mildew]] diseases as well as black spot. In organic production, sulfur is the most important fungicide. It is the only fungicide used in [[organic agriculture|organically]] farmed apple production against the main disease [[apple scab]] under colder conditions. Biosulfur (biologically produced elemental sulfur with hydrophilic characteristics) can also be used for these applications.

Standard-formulation dusting sulfur is applied to crops with a sulfur duster or [[Aerial application|from a dusting plane]]. Wettable sulfur is the commercial name for dusting sulfur formulated with additional ingredients to make it water [[miscibility|miscible]].<ref name="Mohamed-2010" /><ref>{{cite web|url=http://www.freepatentsonline.com/3398227.pdf|title=Method for Preparation of Wettable Sulfur|access-date= 20 May 2010|author= Every, Richard L.|display-authors= etal|date= 20 August 1968}}</ref> It has similar applications and is used as a [[fungicide]] against [[mildew]] and other mold-related problems with plants and soil.

Elemental sulfur powder is used as an "[[organic farming|organic]]" (i.e., "green") [[insecticide]] (actually an [[acaricide]]) against [[tick]]s and [[mite]]s. A common method of application is dusting the clothing or limbs with sulfur powder.

A diluted solution of [[lime sulfur]] (made by combining [[calcium hydroxide]] with elemental sulfur in water) is used as a dip for pets to destroy [[ringworm|ringworm (fungus)]], [[mange]], and other [[cutaneous conditions|dermatoses]] and [[parasitism|parasites]].

Sulfur candles of almost pure sulfur were burned to [[fumigant|fumigate]] structures and wine barrels, but are now considered too toxic for residences.

===Pharmaceuticals===
{{main|Sulfur (pharmacy)}}
Sulfur (specifically [[octasulfur]], S<sub>8</sub>) is used in pharmaceutical skin preparations for the treatment of [[acne]] and other conditions. It acts as a [[keratolytic]] agent and also kills bacteria, fungi, [[scabies]] mites, and other parasites.<ref name="Springer-1978">{{cite book|title=Hagers Handbuch der Pharmazeutischen Praxis|edition=4th|publisher=Springer|location=Berlin–Heidelberg–New York|language=de|date=1978|volume=6B|pages=672–9|isbn=978-3-540-07738-1}}</ref> Precipitated sulfur and colloidal sulfur are used, in form of [[lotion]]s, creams, powders, soaps, and bath additives, for the treatment of [[acne vulgaris]], [[acne rosacea]], and [[seborrhoeic dermatitis]].<ref name="Arzneibuch-Kommentar">{{cite book|title=Arzneibuch-Kommentar. Wissenschaftliche Erläuterungen zum Europäischen Arzneibuch und zum Deutschen Arzneibuch|trans-title=Pharmacopoeia Commentary. Scientific annotations to the European Pharmacopoeia and the German Pharmacopoeia|publisher=Wissenschaftliche Verlagsgesellschaft|location=Stuttgart|date=2004|language=de|isbn=978-3-8047-2575-1|at=Monographie ''Schwefel zum äußerlichen Gebrauch'' [Monograph ''Sulfur for external use'']|edition=23rd}}</ref>

Many drugs contain sulfur.<ref>{{Citation |last1=Scott |first1=Kevin A. |last2=Njardarson |first2=Jon T. |title=Analysis of US FDA-Approved Drugs Containing Sulfur Atoms |date=2019 |url=https://par.nsf.gov/servlets/purl/10218659 |format=PDF |work=Sulfur Chemistry |series=Topics in Current Chemistry Collections |pages=1–34 |editor-last=Jiang |editor-first=Xuefeng |access-date=2023-03-08 |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-030-25598-5_1 |isbn=978-3-030-25598-5 }}</ref> Early examples include antibacterial [[sulfonamide (medicine)|sulfonamides]], known as ''sulfa drugs''. A more recent example is mucolytic [[acetylcysteine]]. Sulfur is a part of many bacterial defense molecules. Most [[β-lactam]] antibiotics, including the [[penicillin]]s, [[cephalosporins]] and [[monobactam]]s contain sulfur.<ref name="Cremlyn-1996" />

=== Batteries ===
Due to their high energy density and the availability of sulfur, there is ongoing research in creating rechargeable [[Lithium–sulfur battery|lithium–sulfur batteries]]. Until now, carbonate electrolytes have caused failures in such batteries after a single cycle. In February 2022, researchers at [[Drexel University]] have not only created a prototypical battery that lasted 4000 recharge cycles, but also found the first monoclinic gamma sulfur that remained stable below 95 degrees Celsius.<ref>{{Cite journal |title=Stabilization of gamma sulfur at room temperature to enable the use of carbonate electrolyte in Li–S batteries |journal=Communications Chemistry |last=Pai |first=Rahul |date=2022-02-10 |volume=5 |issue=1 |page=17 |doi=10.1038/s42004-022-00626-2|pmid=36697747 |pmc=9814344 |s2cid=246704531 |doi-access=free |bibcode=2022CmChe...5...17P }}</ref>