Wikipedia:WikiProject Chemicals/Chembox validation/VerifiedDataSandbox and Selenium tetrachloride: Difference between pages

| Watchedfields = changed

| verifiedrevid = 477163163

| ImageFile2 = Selenium tetrachloride.png

| ImageSize2 =

| ImageName2 =

| OtherNames = Selenium(IV) chloride, tetrachloro-λ⁴-selane

| CASNo_Ref = {{cascite|correct|CAS}}

| CASNo = 10026-03-6

| EC_number = 233-053-5

| RTECS = VS7875000

| PubChem = 66205

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = 4GB8868P5J

| Density = 2.6 g/cm³, solid

| MeltingPt = [[Sublimation (chemistry)|sublimes]] at 191.4&nbsp;°C<ref name="hand">

| edition = 87 | location = Boca Raton, Florida | publisher = CRC Press | isbn = 0-8493-0594-2

| url = https://books.google.com/books?id=lFjg0L-uOxoC&pg=PT872 | access-date = 2008-07-02 }}</ref>

| BoilingPt =

| MolShape = Seesaw (gas phase){{Citation needed|date=February 2012}}

| NFPA-R = 2

| NFPA-S = W

| GHSPictograms = {{GHS06}}{{GHS08}}{{GHS09}}

| GHSSignalWord = Danger

| HPhrases = {{H-phrases|301|331|373|410}}

| PPhrases = {{P-phrases|260|261|264|270|271|273|301+310|304+340|311|314|321|330|391|403+233|405|501}}

| Hazards_ref=<ref name="sa">

{{cite web |url= http://www.sigmaaldrich.com/catalog/search/ProductDetail/ALDRICH/323527/ |title= 323527 Selenium tetrachloride |access-date=2008-07-02 |publisher= Sigma-Aldrich}}</ref>

| OtherCompounds = [[Selenium dichloride]]

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

==Synthesis and structure==

[[File:TeCl4structure.jpg|thumb|left|Structure of selenium tetrachloride]]

The compound is prepared by treating [[selenium]] with [[chlorine]].<ref>{{Cite book | last1 = Nowak | first1 = H. G. | last2 = Suttle | first2 = J. F. | last3 = Parker | first3 = W. E. | last4 = Kleinberg | first4 = J. | chapter = Selenium (IV) Chloride | doi = 10.1002/9780470132364.ch33 | title = Inorganic Syntheses | volume = 5 | pages = 125 | year = 1957 | isbn = 9780470132364 }}</ref> When the reacting selenium is heated, the product [[Sublimation (phase transition)|sublimes]] from the reaction flask. The volatility of selenium tetrachloride can be exploited to purification of selenium.

Solid SeCl₄ is actually a [[tetramer]]ic [[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°.<ref>Kristallstruktur der stabilen Modifikation von SeCl4, Zeitschrift für Naturforschung, 36b, 1660, 1981</ref>

SeCl₄ has often been used as an example for teaching [[VSEPR theory|VSEPR]] rules of [[hypervalent molecule]]s. As such, one would predict four bonds but five electron groups giving rise to a [[Seesaw molecular geometry|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 [[Trigonal pyramidal molecular geometry|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,<ref>Wells, ''Structural Inorganic Chemistry'', fifth ed, Oxford, p. 709, {{ISBN|0-19-855370-6}}</ref> 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.

==Reactions==

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

:SeCl₄ + SbPh₃ → SeCl₂ + Cl₂SbPh₃

Selenium tetrachloride reacts with water to give [[selenous acid|selenous]] and [[hydrochloric acid|hydrochloric]] [[acid]]s:<ref name=Greenwood>{{Greenwood&Earnshaw2nd}}</ref>{{page needed|date=April 2013}}

:SeCl₄ + 3 H₂O → H₂SeO₃ + 4 HCl

Upon treatment with [[selenium dioxide]], it gives [[selenium oxychloride]]:<ref name=Greenwood/>{{page needed|date=April 2013}}

:SeCl₄ + SeO₂ → 2SeOCl₂

==References==

{{Reflist}}

{{Selenium compounds}}

{{Chlorides}}

{{Prostanoidergics}}

[[Category:Selenium(IV) compounds]]

[[Category:Chlorides]]

[[Category:Nonmetal halides]]

[[Category:Chalcohalides]]

[[Category:Selenium halides]]