Selenium tetrachloride

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Selenium tetrachloride
Selenium tetrachloride.png
IUPAC name
Selenium tetrachloride
Other names
Selenium(IV) chloride, tetrachloro-λ4-selane
3D model (JSmol)
ECHA InfoCard 100.030.036 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 233-053-5
PubChem CID
RTECS number
  • VS7875000
  • InChI=1S/Cl4Se/c1-5(2,3)4 Yes check.svgY
  • InChI=1/Cl4Se/c1-5(2,3)4
  • Cl[Se](Cl)(Cl)Cl
Molar mass 220.771 g/mol
Appearancewhite to yellow crystals
Density 2.6 g/cm3, solid
Melting point sublimes at 191.4 °C [1]
decomposes in water
Monoclinic, mS80
C12/c1, No. 15
Seesaw (gas phase)[ citation needed ]
Hazards [2]
GHS labelling:
GHS-pictogram-skull.svg GHS-pictogram-silhouette.svg GHS-pictogram-pollu.svg
H301, H331, H373, H410
P260, P261, P264, P270, P271, P273, P301+P310, P304+P340, P311, P314, P321, P330, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)
NFPA 704.svgHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazard W: Reacts with water in an unusual or dangerous manner. E.g. sodium, sulfuric acid
Flash point non-flammable
Related compounds
Other anions
Selenium tetrafluoride
Selenium tetrabromide
Selenium dioxide
Other cations
Dichlorine monoxide
Sulfur tetrachloride
Tellurium tetrachloride
Related compounds
Selenium dichloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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.


Synthesis and structure

Structure of selenium tetrachloride TeCl4structure.jpg
Structure of selenium tetrachloride

The compound is prepared by treating selenium with chlorine. [3] When the reacting selenium is heated, the product sublimes from the reaction flask. The volatility of selenium tetrachloride can be exploited to purification of selenium.

Solid SeCl4 is actually a tetrameric cubane-type cluster, for which the Se atom of an SeCl6 octahedron sits on four corners of the cube and the bridging Cl atoms sit on the other four corners. The bridging Se-Cl distances are longer than the terminal Se-Cl distances, but all Cl-Se-Cl angles are approximately 90°. [4]

SeCl4 has often been used as an example for teaching VSEPR rules of hypervalent molecules. As such, one would predict four bonds but five electron groups giving rise to a seesaw geometry. This clearly is not the case in the crystal structure. Others have suggested that the crystal structure can be represented as SeCl3+ and Cl. This formulation would predict a pyramidal geometry for the SeCl3+ cation with a Cl-Se-Cl bond angle of approximately 109°. However, this molecule is an excellent example of a situation where maximal bonding cannot be achieved with the simplest molecular formula. The formation of the tetramer (SeCl4)4, [5] with delocalized sigma bonding of the bridging chloride is clearly preferred over a "hypervalent" small molecule. Gaseous SeCl4 contains SeCl2 and chlorine, which recombine upon condensation.


Selenium tetrachloride can be reduced in situ to the dichloride using triphenylstibine:

SeCl4 + SbPh3 → SeCl2 + Cl2SbPh3

Selenium tetrachloride reacts with water to give selenous and hydrochloric acids: [6] [ page needed ]

SeCl4 + 3 H2O → H2SeO3 + 4 HCl

Upon treatment with selenium dioxide, it gives selenium oxychloride: [6] [ page needed ]

SeCl4 + SeO2 → 2SeOCl2

Related Research Articles

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

Silicon tetrachloride or tetrachlorosilane is the inorganic compound with the formula SiCl4. It is a colorless volatile liquid that fumes in air. It is used to produce high purity silicon and silica for commercial applications. It is a part of the chlorosilane family.

<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">Lead(II) chloride</span> Chemical compound

Lead(II) chloride (PbCl2) is an inorganic compound which is a white solid under ambient conditions. It is poorly soluble in water. Lead(II) chloride is one of the most important lead-based reagents. It also occurs naturally in the form of the mineral cotunnite.

Neodymium(III) chloride or neodymium trichloride is a chemical compound of neodymium and chlorine with the formula NdCl3. This anhydrous compound is a mauve-colored solid that rapidly absorbs water on exposure to air to form a purple-colored hexahydrate, NdCl3·6H2O. Neodymium(III) chloride is produced from minerals monazite and bastnäsite using a complex multistage extraction process. The chloride has several important applications as an intermediate chemical for production of neodymium metal and neodymium-based lasers and optical fibers. Other applications include a catalyst in organic synthesis and in decomposition of waste water contamination, corrosion protection of aluminium and its alloys, and fluorescent labeling of organic molecules (DNA).

Tin(IV) chloride, also known as tin tetrachloride or stannic chloride, is an inorganic compound with the formula SnCl4. It is a colorless hygroscopic liquid, which fumes on contact with air. It is used as a precursor to other tin compounds. It was first discovered by Andreas Libavius (1550–1616) and was known as spiritus fumans libavii.

<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.

<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.

In inorganic chemistry, chlorosilanes are a group of reactive, chlorine-containing chemical compounds, related to silane and used in many chemical processes. Each such chemical has at least one silicon-chlorine bond. Trichlorosilane is produced on the largest scale. The parent chlorosilane is silicon tetrachloride.

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

Scandium(III) chloride is the inorganic compound with the formula ScCl3. It is a white, high-melting ionic compound, which is deliquescent and highly water-soluble. This salt is mainly of interest in the research laboratory. Both the anhydrous form and hexahydrate (ScCl3•6H2O) are commercially available.

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

Phosphoryl chloride is a colourless liquid with the formula POCl3. It hydrolyses in moist air releasing phosphoric acid and fumes of hydrogen chloride. It is manufactured industrially on a large scale from phosphorus trichloride and oxygen or phosphorus pentoxide. It is mainly used to make phosphate esters such as tricresyl phosphate.

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

Tellurium tetrachloride is the inorganic compound with the empirical formula TeCl4. The compound is volatile, subliming at 200 °C at 0.1 mmHg. Molten TeCl4 is ionic, dissociating into TeCl3+ and Te2Cl102−.

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

Platinum(IV) chloride is the inorganic compound of platinum and chlorine with the empirical formula PtCl4. This brown solid features platinum in the 4+ oxidation state.

Technetium compounds are chemical compounds containing the chemical element technetium. Technetium can form multiple oxidation states, but often forms in the +4 and +7 oxidation states. Because technetium is radioactive, technetium compounds are extremely rare on Earth.

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

Germanium dichloride is a chemical compound of germanium and chlorine with the formula GeCl2. It is a yellow solid. Germanium dichloride is an example of a compound featuring germanium in the +2 oxidation state.

Selenium monochloride or diselenium dichloride is an inorganic compound with the formula Se2Cl2. 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.

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

Sulfur tetrachloride is an inorganic compound with chemical formula SCl4. It has only been obtained as an unstable pale yellow solid. The corresponding SF4 is a stable, useful reagent.

<span class="mw-page-title-main">Metal halides</span>

Metal halides are compounds between metals and halogens. Some, such as sodium chloride are ionic, while others are covalently bonded. A few metal halides are discrete molecules, such as uranium hexafluoride, but most adopt polymeric structures, such as palladium chloride.

In chemistry, molecular oxohalides (oxyhalides) are a group of chemical compounds in which both oxygen and halogen atoms are attached to another chemical element A in a single molecule. They have the general formula AOmXn, where X is a halogen. Known oxohalides have fluorine (F), chlorine (Cl), bromine (Br), and/or iodine (I) in their molecules. The element A may be a main group element, a transition element, a rare earth element or an actinide. The term oxohalide, or oxyhalide, may also refer to minerals and other crystalline substances with the same overall chemical formula, but having an ionic structure.

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

Lead tetrachloride, also known as lead(IV) chloride, has the molecular formula PbCl4. It is a yellow, oily liquid which is stable below 0 °C, and decomposes at 50 °C. It has a tetrahedral configuration, with lead as the central atom. The Pb–Cl covalent bonds have been measured to be 247 pm and the bond energy is 243 kJ⋅mol−1.

Indium(II) chloride is an inorganic compound, an indium metal salt and hydrochloric acid with the formula InCl2. The compound forms colorless crystals, reacts with water. This is one of three known indium chlorides.


  1. Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, Florida: CRC Press. p. 487. ISBN   0-8493-0594-2 . Retrieved 2008-07-02.
  2. "323527 Selenium tetrachloride". Sigma-Aldrich. Retrieved 2008-07-02.
  3. Nowak, H. G.; Suttle, J. F.; Parker, W. E.; Kleinberg, J. (1957). "Selenium (IV) Chloride". Inorganic Syntheses. Vol. 5. p. 125. doi:10.1002/9780470132364.ch33. ISBN   9780470132364.
  4. Kristallstruktur der stabilen Modifikation von SeCl4, Zeitschrift für Naturforschung, 36b, 1660, 1981
  5. Wells, Structural Inorganic Chemistry, fifth ed, Oxford, p. 709, ISBN   0-19-855370-6
  6. 1 2 Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN   978-0-08-037941-8.