Editing Chalcogen (section)

==Compounds==

===With halogens=== <!-- Chalcohalide redirects here -->
Chalcogens also form compounds with [[halogen]]s known as '''chalcohalides''', or '''chalcogen halides'''. The majority of simple chalcogen halides are well-known and widely used as chemical [[reagent]]s. However, more complicated chalcogen halides, such as sulfenyl, sulfonyl, and sulfuryl halides, are less well known to science. Out of the compounds consisting purely of chalcogens and halogens, there are a total of 13 chalcogen fluorides, nine chalcogen chlorides, eight chalcogen bromides, and six chalcogen iodides that are known.{{dubious|date=September 2014}} The heavier chalcogen halides often have significant molecular interactions. Sulfur fluorides with low valences are fairly unstable and little is known about their properties.{{dubious|date=September 2014}} However, sulfur fluorides with high valences, such as [[sulfur hexafluoride]], are stable and well-known. [[Sulfur tetrafluoride]] is also a well-known sulfur fluoride. Certain selenium fluorides, such as [[selenium difluoride]], have been produced in small amounts. The crystal structures of both [[selenium tetrafluoride]] and [[tellurium tetrafluoride]] are known. Chalcogen chlorides and bromides have also been explored. In particular, selenium dichloride and sulfur dichloride can react to form [[Organoselenium chemistry|organic selenium compounds]]. Dichalcogen dihalides, such as Se<sub>2</sub>Cl<sub>2</sub> also are known to exist. There are also mixed chalcogen-halogen compounds. These include SeSX, with X being chlorine or bromine.{{dubious|date=September 2014}} Such compounds can form in mixtures of [[sulfur dichloride]] and selenium halides. These compounds have been fairly recently structurally characterized, as of 2008. In general, diselenium and disulfur chlorides and bromides are useful chemical reagents. Chalcogen halides with attached metal atoms are soluble in organic solutions.{{dubious|date=September 2014}} One example of such a compound is {{chem2|[[Mo]]S2Cl3}}. Unlike selenium chlorides and bromides, selenium [[iodide]]s have not been isolated, as of 2008, although it is likely that they occur in solution. Diselenium diiodide, however, does occur in equilibrium with selenium atoms and iodine molecules. Some tellurium halides with low valences, such as {{chem2|Te2Cl2}} and {{chem2|Te2Br2}}, form [[polymer]]s when in the [[Solid-state chemistry|solid state]]. These tellurium halides can be synthesized by the reduction of pure tellurium with [[superhydride]] and reacting the resulting product with tellurium tetrahalides. Ditellurium dihalides tend to get less stable as the halides become lower in atomic number and atomic mass. Tellurium also forms iodides with even fewer iodine atoms than diiodides. These include TeI and Te<sub>2</sub>I. These compounds have extended structures in the solid state. Halogens and chalcogens can also form halochalcogenate [[anion]]s.<ref name="handbook"/>

===Organic===
[[Alcohol (chemistry)|Alcohol]]s, [[phenol]]s and other similar compounds contain oxygen. However, in [[thiol]]s, [[selenol]]s and [[tellurol]]s; sulfur, selenium, and tellurium replace oxygen. Thiols are better known than selenols or tellurols. Aside from alcohols, thiols are the most stable chalcogenols and tellurols are the least stable, being unstable in heat or light. Other organic chalcogen compounds include [[thioether]]s, [[selenoether]]s and telluroethers. Some of these, such as [[dimethyl sulfide]], [[diethyl sulfide]], and [[dipropyl sulfide]] are commercially available. Selenoethers are in the form of [[side chain|R]]<sub>2</sub>Se or [[side chain|R]]SeR. Telluroethers such as [[dimethyl telluride]] are typically prepared in the same way as thioethers and selenoethers. Organic chalcogen compounds, especially organic sulfur compounds, have the tendency to smell unpleasant. Dimethyl telluride also smells unpleasant,<ref>{{cite encyclopedia |url=https://www.britannica.com/EBchecked/topic/592252/thiol |title=thiol (chemical compound)|encyclopedia = [[Encyclopædia Britannica]] |access-date=November 25, 2013}}</ref> and [[selenophenol]] is renowned for its "metaphysical stench".<ref>{{cite web|vauthors = Lowe D|url=http://pipeline.corante.com/archives/2012/05/15/things_i_wont_work_with_selenophenol.php |title=Things I Won't Work With: Selenophenol |work=In the Pipeline |date=May 15, 2012 |access-date=November 25, 2013 |archive-url=https://web.archive.org/web/20120515170845/http://pipeline.corante.com/archives/2012/05/15/things_i_wont_work_with_selenophenol.php |archive-date=May 15, 2012 |df=mdy }}</ref> There are also [[thioketone]]s, [[selenoketone]]s, and [[telluroketones]]. Out of these, thioketones are the most well-studied with 80% of chalcogenoketones papers being about them. Selenoketones make up 16% of such papers and telluroketones make up 4% of them. Thioketones have well-studied non-linear electric and photophysical properties. Selenoketones are less stable than thioketones and telluroketones are less stable than selenoketones. Telluroketones have the highest level of [[Chemical polarity|polarity]] of chalcogenoketones.<ref name="handbook"/>

===With metals===

There is a very large number of metal chalcogenides. There are also ternary compounds containing [[alkali metal]]s and [[transition metal]]s. Highly metal-rich metal chalcogenides, such as [[lutetium|Lu]]<sub>7</sub>Te and Lu<sub>8</sub>Te have domains of the metal's crystal lattice containing chalcogen atoms. While these compounds do exist, analogous chemicals that contain [[lanthanum]], [[praseodymium]], [[gadolinium]], [[holmium]], [[terbium]], or [[ytterbium]] have not been discovered, as of 2008. The [[boron group]] metals aluminum, [[gallium]], and [[indium]] also form bonds to chalcogens. The Ti<sup>3+</sup> ion forms chalcogenide [[Dimer (chemistry)|dimers]] such as Ti[[thallium|Tl]]<sub>5</sub>Se<sub>8</sub>. Metal chalcogenide dimers also occur as lower tellurides, such as Zr<sub>5</sub>Te<sub>6</sub>.<ref name="handbook"/>

Elemental chalcogens react with certain lanthanide compounds to form lanthanide clusters rich in chalcogens.{{dubious|date=September 2014}} [[Uranium]](IV) chalcogenol compounds also exist. There are also [[transition metal]] chalcogenols which have potential to serve as [[catalyst]]s and stabilize [[nanoparticle]]s.<ref name="handbook"/>

===With pnictogens===

[[File:Sulfid bismutitý.PNG|thumb|Bismuth sulfide, a pnictogen chalcogenide]]
Compounds with chalcogen-[[phosphorus]] bonds have been explored for more than 200 years. These compounds include unsophisticated phosphorus chalcogenides as well as large molecules with biological roles and phosphorus-chalcogen compounds with metal clusters. These compounds have numerous applications, including organo-phosphate insecticides, [[Match#The strike-anywhere match|strike-anywhere matches]] and [[quantum dot]]s. A total of 130,000 compounds with at least one phosphorus-sulfur bond, 6000 compounds with at least one phosphorus-selenium bond, and 350 compounds with at least one phosphorus-tellurium bond have been discovered.{{citation needed|date=September 2014}} The decrease in the number of chalcogen-phosphorus compounds further down the periodic table is due to diminishing bond strength. Such compounds tend to have at least one phosphorus atom in the center, surrounded by four chalcogens and [[side chain]]s. However, some phosphorus-chalcogen compounds also contain hydrogen (such as secondary [[phosphine]] chalcogenides) or nitrogen (such as dichalcogenoimidodiphosphates). [[Phosphorus selenide]]s are typically harder to handle that phosphorus sulfides, and compounds in the form P<sub>x</sub>Te<sub>y</sub> have not been discovered. Chalcogens also bond with other [[pnictogens]], such as [[arsenic]], [[antimony]], and [[bismuth]]. Heavier chalcogen pnictides tend to form [[ribbon]]-like polymers instead of individual molecules. Chemical formulas of these compounds include Bi<sub>2</sub>S<sub>3</sub> and Sb<sub>2</sub>Se<sub>3</sub>. Ternary chalcogen pnictides are also known. Examples of these include P<sub>4</sub>O<sub>6</sub>Se and P<sub>3</sub>SbS<sub>3</sub>. [[Salt (chemistry)|salts]] containing chalcogens and pnictogens also exist. Almost all chalcogen pnictide salts are typically in the form of [Pn<sub>x</sub>E<sub>4x</sub>]<sup>3−</sup>, where Pn is a pnictogen and E is a chalcogen.{{dubious|date=September 2014}} Tertiary phosphines can react with chalcogens to form compounds in the form of R<sub>3</sub>PE, where E is a chalcogen. When E is sulfur, these compounds are relatively stable, but they are less so when E is selenium or tellurium. Similarly, secondary phosphines can react with chalcogens to form secondary phosphine chalcogenides. However, these compounds are in a state of [[Chemical equilibrium|equilibrium]] with chalcogenophosphinous acid. Secondary phosphine chalcogenides are [[weak acids]].<ref name="handbook"/> Binary compounds consisting of antimony or arsenic and a chalcogen. These compounds tend to be colorful and can be created by a reaction of the constituent elements at temperatures of {{convert|500|to|900|C|F}}.<ref>{{Citation|author1=A. Earnshaw |author2=Norman Greenwood |url = https://books.google.com/books?id=EvTI-ouH3SsC&q=chalcogen|title = Chemistry of the Elements|date = November 11, 1997|publisher=Elsevier |access-date = February 12, 2014|isbn = 9780080501093}}</ref>

===Other===
Chalcogens form single bonds and double bonds with other [[carbon group]] elements than carbon, such as [[silicon]], [[germanium]], and [[tin]]. Such compounds typically form from a reaction of carbon group halides and chalcogenol salts or chalcogenol [[base (chemistry)|bases]]. Cyclic compounds with chalcogens, carbon group elements, and boron atoms exist, and occur from the reaction of boron dichalcogenates and carbon group metal halides. Compounds in the form of M-E, where M is silicon, germanium, or tin, and E is sulfur, selenium or tellurium have been discovered. These form when carbon group [[hydride]]s react or when heavier versions of [[carbene]]s react.{{dubious|date=September 2014}} Sulfur and tellurium can bond with organic compounds containing both silicon and phosphorus.<ref name="handbook"/>

All of the chalcogens form [[hydride]]s. In some cases this occurs with chalcogens bonding with two hydrogen atoms.<ref name="ReferenceB"/> However [[tellurium hydride]] and [[polonium hydride]] are both volatile and highly [[labile]].<ref name = "holleman">{{cite book|editor1=Holleman, Arnold F. |editor2=Wiber, Egon |editor3=Wiberg, Nils |url = https://books.google.com/books?id=Mtth5g59dEIC&pg=PA470|title = Inorganic Chemistry|pages=470 ff|isbn = 978-0-12-352651-9|year=2001|publisher=Academic Press }}</ref> Also, oxygen can bond to hydrogen in a 1:1 ratio as in [[hydrogen peroxide]], but this compound is unstable.<ref name="wisc"/>

Chalcogen compounds form a number of [[interchalcogen]]s. For instance, sulfur forms the toxic [[sulfur dioxide]] and [[sulfur trioxide]].<ref name="wisc"/> Tellurium also forms oxides. There are some chalcogen sulfides as well. These include [[selenium sulfide]], an ingredient in some [[shampoo]]s.<ref name="The Elements"/>

Since 1990, a number of [[boride]]s with chalcogens bonded to them have been detected. The chalcogens in these compounds are mostly sulfur, although some do contain selenium instead. One such chalcogen boride consists of two molecules of [[dimethyl sulfide]] attached to a boron-hydrogen molecule. Other important boron-chalcogen compounds include [[macropolyhedral]] systems. Such compounds tend to feature sulfur as the chalcogen. There are also chalcogen borides with two, three, or four chalcogens. Many of these contain sulfur but some, such as Na<sub>2</sub>B<sub>2</sub>Se<sub>7</sub> contain selenium instead.<ref>{{cite book|editor = Devillanova, Francesco A. |title=Handbook of chalcogen chemistry|url=https://books.google.com/books?id=IvGnUAaSqOsC|year = 2007|publisher=Royal Society of Chemistry |isbn = 978-0-85404-366-8 |access-date=November 25, 2013}}</ref>