Selenium monochloride

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Diselenium dichloride
Names
IUPAC name
Diselenium dichloride
Other names
  • 1,2-Dichlorodiselane
  • Dichlorodiselane
  • Dichlorodiselenide
  • Selenium chloride
  • Selenium monochloride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.030.022 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 233-037-8
PubChem CID
UNII
  • InChI=1S/Cl2Se2/c1-3-4-2 X mark.svgN
    Key: VIEXQFHKRAHTQS-UHFFFAOYSA-N X mark.svgN
  • InChI=1/Cl2Se2/c1-3-4-2
    Key: VIEXQFHKRAHTQS-UHFFFAOYAC
  • Cl[Se][Se]Cl
Properties
Se2Cl2
Molar mass 228.84 g·mol−1
AppearanceReddish-brown oily liquid
Density 2.7741 g/cm3
Melting point −85 °C (−121 °F; 188 K)
Boiling point 127 °C (261 °F; 400 K) at 0.997 atm
insoluble
Solubility in other solventsSoluble in chloroform, carbon disulfide, and acetonitrile
−94.8·10−6 cm3/mol
Hazards
GHS labelling:
GHS-pictogram-acid.svg GHS-pictogram-skull.svg GHS-pictogram-silhouette.svg GHS-pictogram-pollu.svg
Danger
H301, H311, H314, H331, H373, H410
P260, P261, P264, P270, P271, P273, P280, P301+P310, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P311, P312, P314, P321, P322, P330, P361, P363, P391, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Selenium monochloride or diselenium dichloride is an inorganic compound with the formula Se 2 Cl 2. Although a common name for the compound is selenium monochloride, reflecting its empirical formula, IUPAC does not recommend that name, instead preferring the more descriptive diselenium dichloride.

Contents

Diselenium dichloride is a reddish-brown, oily liquid that hydrolyses slowly. It exists in chemical equilibrium with SeCl2, SeCl4, chlorine, and elemental selenium. [1] Diselenium dichloride is mainly used as a reagent for the synthesis of Se-containing compounds.

Structure and properties

Dielenium dichloride has the connectivity Cl−Se−Se−Cl. With a nonplanar structure, it has C2 molecular symmetry, similar to hydrogen peroxide and disulfur dichloride, which is referred to as gauche. The Se-Se bond length is 223 pm, and the Se-Cl bond lengths are 220 pm. The dihedral angle between the Cla−Se−Se and Se−Se−Clb planes is 87°. [2]

Preparation

Early routes to diselenium dichloride involved chlorination of elemental selenium. [3] An improved method involves the reaction of a mixture of selenium, selenium dioxide, and hydrochloric acid: [4]

3 Se + SeO2 + 4 HCl → 2 Se2Cl2 + 2 H2O

A dense layer of diselenium dichloride settles from the reaction mixture, which can be purified by dissolving it in fuming sulfuric acid and reprecipitating it with hydrochloric acid. A second method for the synthesis involves the reaction of selenium with oleum and hydrochloric acid: [4]

2 Se + 2 SO3 + 3 HCl → Se2Cl2 + SO2 + H2O + SO2(OH)Cl

The crude diselenium dichloride is removed via separatory funnel. Diselenium dichloride cannot be distilled without decomposition, even at reduced pressure. [4]

In acetonitrile solutions, it exists in equilibrium with SeCl2 and SeCl4. [5] Selenium dichloride degrades to diselenium dichloride after a few minutes at room temperature: [6]

3 SeCl2 → Se2Cl2 + SeCl4

Reactions

Diselenium dichloride is an electrophilic selenizing agent, and thus it reacts with simple alkenes to give bis(β-chloroalkyl)selenide and bis(chloroalkyl)selenium dichloride. It converts hydrazones of hindered ketones into the corresponding selenoketones, the structural analogs of ketones whereby the oxygen atom is replaced with a selenium atom. [7] Finally, the compound has been used to introduce bridging selenium ligands between the metal atoms of some iron and chromium carbonyl complexes. [7]

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Aqua regia is a mixture of nitric acid and hydrochloric acid, optimally in a molar ratio of 1:3. Aqua regia is a fuming liquid. Freshly prepared aqua regia is colorless, but it turns yellow, orange or red within seconds from the formation of nitrosyl chloride and nitrogen dioxide. It was named by alchemists because it can dissolve noble metals like gold and platinum, though not all metals.

Iron(III) chloride describes the inorganic compounds with the formula FeCl3(H2O)x. Also called ferric chloride, these compounds are some of the most important and commonplace compounds of iron. They are available both in anhydrous and in hydrated forms which are both hygroscopic. They feature iron in its +3 oxidation state. The anhydrous derivative is a Lewis acid, while all forms are mild oxidizing agents. It is used as a water cleaner and as an etchant for metals.

<span class="mw-page-title-main">Titanium tetrachloride</span> Inorganic chemical compound

Titanium tetrachloride is the inorganic compound with the formula TiCl4. It is an important intermediate in the production of titanium metal and the pigment titanium dioxide. TiCl4 is a volatile liquid. Upon contact with humid air, it forms thick clouds of titanium dioxide and hydrochloric acid, a reaction that was formerly exploited for use in smoke machines. It is sometimes referred to as "tickle" or "tickle 4", as a phonetic representation of the symbols of its molecular formula.

<span class="mw-page-title-main">Manganese(II) chloride</span> Chemical compound

Manganese(II) chloride is the dichloride salt of manganese, MnCl2. This inorganic chemical exists in the anhydrous form, as well as the dihydrate (MnCl2·2H2O) and tetrahydrate (MnCl2·4H2O), with the tetrahydrate being the most common form. Like many Mn(II) species, these salts are pink, with the paleness of the color being characteristic of transition metal complexes with high spin d5 configurations.

<span class="mw-page-title-main">Chromium(III) chloride</span> Chemical compound

Chromium(III) chloride (also called chromic chloride) is an inorganic chemical compound with the chemical formula CrCl3. It forms several hydrates with the formula CrCl3·nH2O, among which are hydrates where n can be 5 (chromium(III) chloride pentahydrate CrCl3·5H2O) or 6 (chromium(III) chloride hexahydrate CrCl3·6H2O). The anhydrous compound with the formula CrCl3 are violet crystals, while the most common form of the chromium(III) chloride are the dark green crystals of hexahydrate, CrCl3·6H2O. Chromium chlorides find use as catalysts and as precursors to dyes for wool.

Iron(II) chloride, also known as ferrous chloride, is the chemical compound of formula FeCl2. It is a paramagnetic solid with a high melting point. The compound is white, but typical samples are often off-white. FeCl2 crystallizes from water as the greenish tetrahydrate, which is the form that is most commonly encountered in commerce and the laboratory. There is also a dihydrate. The compound is highly soluble in water, giving pale green solutions.

<span class="mw-page-title-main">Cadmium chloride</span> Chemical compound

Cadmium chloride is a white crystalline compound of cadmium and chloride, with the formula CdCl2. This salt is a hygroscopic solid that is highly soluble in water and slightly soluble in alcohol. The crystal structure of cadmium chloride (described below), is a reference for describing other crystal structures. Also known are CdCl2•H2O and the hemipentahydrate CdCl2•2.5H2O.

<span class="mw-page-title-main">Gold(III) chloride</span> Chemical compound

Gold(III) chloride, traditionally called auric chloride, is an inorganic compound of gold and chlorine with the molecular formula Au2Cl6. The "III" in the name indicates that the gold has an oxidation state of +3, typical for many gold compounds. It has two forms, the monohydrate (AuCl3·H2O) and the anhydrous form, which are both hygroscopic and light-sensitive solids. This compound is a dimer of AuCl3. This compound has a few uses, such as an oxidizing agent and for catalyzing various organic reactions.

<span class="mw-page-title-main">Sulfuryl chloride</span> Chemical compound

Sulfuryl chloride is an inorganic compound with the formula SO2Cl2. At room temperature, it is a colorless liquid with a pungent odor. Sulfuryl chloride is not found in nature, as can be inferred from its rapid hydrolysis.

<span class="mw-page-title-main">Hafnium tetrachloride</span> Chemical compound

Hafnium(IV) chloride is the inorganic compound with the formula HfCl4. This colourless solid is the precursor to most hafnium organometallic compounds. It has a variety of highly specialized applications, mainly in materials science and as a catalyst.

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<span class="mw-page-title-main">Vanadium oxytrichloride</span> Chemical compound

Vanadium oxytrichloride is the inorganic compound with the formula VOCl3. This yellow distillable liquid hydrolyzes readily in air. It is an oxidizing agent. It is used as a reagent in organic synthesis. Samples often appear red or orange owing to an impurity of vanadium tetrachloride.

<span class="mw-page-title-main">Disulfur dichloride</span> Chemical compound

Disulfur dichloride is the inorganic compound of sulfur and chlorine with the formula S2Cl2. It is an amber oily liquid.

<span class="mw-page-title-main">Arsenic trichloride</span> Chemical compound

Arsenic trichloride is an inorganic compound with the formula AsCl3, also known as arsenous chloride or butter of arsenic. This poisonous oil is colourless, although impure samples may appear yellow. It is an intermediate in the manufacture of organoarsenic compounds.

<span class="mw-page-title-main">Selenium tetrafluoride</span> Chemical compound

Selenium tetrafluoride (SeF4) is an inorganic compound. It is a colourless liquid that reacts readily with water. It can be used as a fluorinating reagent in organic syntheses (fluorination of alcohols, carboxylic acids or carbonyl compounds) and has advantages over sulfur tetrafluoride in that milder conditions can be employed and it is a liquid rather than a gas.

<span class="mw-page-title-main">Selenium compounds</span> Chemical compounds containing selenium

Selenium compounds are compounds containing the element selenium (Se). Among these compounds, selenium has various oxidation states, the most common ones being −2, +4, and +6. Selenium compounds exist in nature in the form of various minerals, such as clausthalite, guanajuatite, tiemannite, crookesite etc., and can also coexist with sulfide minerals such as pyrite and chalcopyrite. For many mammals, selenium compounds are essential. For example, selenomethionine and selenocysteine are selenium-containing amino acids present in the human body. Selenomethionine participates in the synthesis of selenoproteins. The reduction potential and pKa (5.47) of selenocysteine are lower than those of cysteine, making some proteins have antioxidant activity. Selenium compounds have important applications in semiconductors, glass and ceramic industries, medicine, metallurgy and other fields.

Niobocene dichloride is the organometallic compound with the formula (C5H5)2NbCl2, abbreviated Cp2NbCl2. This paramagnetic brown solid is a starting reagent for the synthesis of other organoniobium compounds. The compound adopts a pseudotetrahedral structure with two cyclopentadienyl and two chloride substituents attached to the metal. A variety of similar compounds are known, including Cp2TiCl2.

<span class="mw-page-title-main">Selenium tetrachloride</span> Chemical compound

Selenium tetrachloride is the inorganic compound composed with the formula SeCl4. This compound exists as yellow to white volatile solid. It is one of two commonly available selenium chlorides, the other example being selenium monochloride, Se2Cl2. SeCl4 is used in the synthesis of other selenium compounds.

In organometallic chemistry, bent metallocenes are a subset of metallocenes. In bent metallocenes, the ring systems coordinated to the metal are not parallel, but are tilted at an angle. A common example of a bent metallocene is Cp2TiCl2. Several reagents and much research is based on bent metallocenes.

<span class="mw-page-title-main">Selenium dichloride</span> Chemical compound

Selenium dichloride is the inorganic compound with the formula SeCl2. It forms red-brown solutions in ethers. Selenium dichloride has been prepared by treating gray selenium with sulfuryl chloride. Adducts of selenium dichloride with thioethers and thioureas are well characterized. Related complexes of tellurium dichloride are known.

References

  1. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN   978-0-08-037941-8.
  2. ↑ Kniep, Rüdiger; Körte, Lutz; Mootz, Dietrich (1 January 1983). "Kristallstrukturen von Verbindungen A2X2 (A = S, Se; X = Cl, Br)". Zeitschrift für Naturforschung B. 38 (1): 1–6. doi: 10.1515/znb-1983-0102 .
  3. ↑ Lenher, Victor; Kao, C. H. (1925). "The Preparation of Selenium Monochloride and Monobromide". Journal of the American Chemical Society. 47 (3): 772–774. doi:10.1021/ja01680a025.
  4. 1 2 3 Fehér, F. (1963). "Diselenium Dichloride". In Brauer, G. (ed.). Handbook of Preparative Inorganic Chemistry. Vol. 1 (2nd ed.). New York: Academic Press. pp. 422–423.
  5. ↑ Lamoureux, Marc; Milne, John (1990). "Selenium chloride and bromide equilibria in aprotic solvents; a Se77 NMR study". Polyhedron. 9 (4): 589–595. doi:10.1016/S0277-5387(00)86238-5.
  6. ↑ Maaninen, Arto; Chivers, Tristram; Parvez, Masood; Pietikäinen, Jarkko; Laitinen, Risto S. (1999). "Syntheses of THF Solutions of SeX2(X = Cl, Br) and a New Route to Selenium Sulfides SenS8−n(n = 1−5): X-ray Crystal Structures of SeCl2(tht)2 and SeCl2·tmtu". Inorganic Chemistry. 38 (18): 4093–4097. doi:10.1021/ic981430h.
  7. 1 2 Back, Thomas G.; Moussa, Ziad (2003). "Diselenium Dichloride". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rn00201. ISBN   0-471-93623-5.
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