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

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 464388785

| Name = Selenium trioxide

| ImageFileL1 = Selenium trioxide.svg

| ImageNameL1 = Structural formula of the monomer as found in the gas phase

| ImageFileR1 = Selenium-trioxide-3D-spacefill.png

| ImageNameR1 = Space-filling model of the monomer as found in the gas phase

| last = Lide

| first = David R.

| year = 1998

| title = Handbook of Chemistry and Physics

| edition = 87

| location = Boca Raton, Florida

| publisher = CRC Press

| isbn = 0-8493-0594-2

| pages = 4–81

| OtherNames =

|Section1={{Chembox Identifiers

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| SMILES = O=[Se](=O)=O

| SMILES_Comment = monomer

| SMILES1 = O=[Se]0(=O)O[Se](=O)(=O)O[Se](=O)(=O)O[Se](=O)(=O)O0

| SMILES1_Comment = cyclic tetramer

| CASNo_Ref = {{cascite|changed|??}}

| CASNo = 13768-86-0

| PubChem = 115128

|Section2={{Chembox Properties

| Formula = SeO₃

| MolarMass = 126.96 g/mol

| Appearance = white [[hygroscopic]] crystals

| Density = 3.44 g/cm³

| Solubility = very soluble

| MeltingPtC = 118.35

| BoilingPt = sublimes

|Section3={{Chembox Structure

| CrystalStruct = [[tetragonal]]

|Section7={{Chembox Hazards

| GHS_ref=<ref>{{cite web |title=C&L Inventory |url=https://echa.europa.eu/information-on-chemicals/cl-inventory-database/-/discli/details/153441 |website=echa.europa.eu |access-date=16 December 2021}}</ref>

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

| GHSSignalWord = Danger

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

| PPhrases = {{P-phrases|}}

| NFPA-H = 4

| NFPA-F = 0

| NFPA-R = 2

| NFPA-S = OX

| LD50 = 7 mg/kg (rat, oral)<br/>7.08 mg/kg (mouse, oral)<br/>5.06 mg/kg (guinea pig, oral)<br/>2.25 mg/kg (rabbit, oral)<br/>13 mg/kg (horse, oral)<ref name=IDLH>{{IDLH|7782492|Selenium compounds (as Se)}}</ref>

| LC50 = 13 mg/kg (pig, oral)<br/>9.9 mg/kg (cow, oral)<br/>3.3 mg/kg (goat, oral)<br/>3.3 mg/kg (sheep, oral)<ref name=IDLH/>

'''Selenium trioxide''' is the [[inorganic compound]] with the formula [[Selenium|Se]][[Oxygen|O₃]]. It is white, hygroscopic solid. It is also an [[oxidizing agent]] and a [[Lewis acid]]. It is of academic interest as a precursor to Se(VI) compounds.<ref name = "Wiberg&Holleman">Egon Wiberg, Arnold Frederick Holleman (2001) ''Inorganic Chemistry'', Elsevier {{ISBN|0123526515}}</ref>

==Preparation==

Selenium trioxide is difficult to prepare because it is unstable with respect to [[selenium dioxide|the dioxide]]:

:2 SeO₃ → 2 SeO₂ + O₂

It has been generated in a number of ways despite the fact that the dioxide does not combust under normal conditions.<ref name = "Wiberg&Holleman"/> One method entails dehydration of anhydrous [[selenic acid]] with [[phosphorus pentoxide]] at 150–160&nbsp;°C. Another method is the reaction of liquid [[sulfur trioxide]] with [[potassium selenate]].

:SO₃ + K₂SeO₄ → K₂SO₄ + SeO₃

==Reactions==

In its chemistry SeO₃ generally resembles [[sulfur trioxide]], SO₃, rather than [[tellurium trioxide]], TeO₃.<ref name="Wiberg&Holleman" /> The substance reacts [[Explosion|explosively]] with [[Reducing agent|oxidizable]] [[Organic compound|organic compounds]].{{Sfn|Schmidt|Bornmann|Wilhelm|1963}}

At 120&nbsp;°C SeO₃ reacts with [[selenium dioxide]] to form the Se(VI)-Se(IV) compound diselenium pentaoxide:<ref>Z. Žák "Crystal structure of diselenium pentoxide Se₂O₅" Zeitschrift für anorganische und allgemeine Chemie 1980, volume 460, pp. 81–85. {{doi|10.1002/zaac.19804600108}}</ref>

:SeO₃ + SeO₂ → Se₂O₅

It reacts with [[selenium tetrafluoride]] to form [[selenoyl fluoride]], the selenium analogue of [[sulfuryl fluoride]]

:2SeO₃ + SeF₄ → 2SeO₂F₂ + SeO₂

As with SO₃ adducts are formed with [[Lewis base]]s such as [[pyridine]], [[dioxane]] and [[diethyl ether|ether]].<ref name="Wiberg&Holleman" />

With [[lithium oxide]] and [[sodium oxide]] it reacts to form salts of Se^VIO₅⁴⁻ and Se^VIO₆⁶⁻:<ref name="Devillanova">Handbook of Chalcogen Chemistry: New Perspectives in Sulfur, Selenium and Tellurium, Francesco A. Devillanova, Royal Society of Chemistry, 2007, {{ISBN|9780854043668}}</ref> With Li₂O, it gives Li₄SeO₅, containing the trigonal pyramidal anion Se^VIO₅⁴⁻ with equatorial bonds, 170.6–171.9&nbsp;pm; and longer axial Se−O bonds of 179.5&nbsp;pm. With Na₂O it gives Na₄SeO₅, containing the square pyramidal Se^VIO₅⁴⁻, with Se−O bond lengths ranging from range 172.9 → 181.5&nbsp;pm, and Na₁₂(SeO₄)₃(SeO₆), containing octahedral Se^VIO₆⁶⁻. Se^VIO₆⁶⁻ is the conjugate base of the unknown orthoselenic acid (Se(OH)₆).

==Structure==

In the solid phase SeO₃ consists of cyclic tetramers, with an 8 membered (Se−O)₄ ring. Selenium atoms are 4-coordinate, bond lengths being Se−O bridging are 175&nbsp;pm and 181&nbsp;pm, non-bridging 156 and 154&nbsp;pm.<ref name="Devillanova"/>

SeO₃ in the gas phase consists of tetramers and monomeric SeO₃ which is trigonal planar with an Se−O bond length of 168.78&nbsp;pm.<ref name="BrassingtonEdwards1978">{{cite journal|last1=Brassington|first1=N. J.|last2=Edwards|first2=H. G. M.|last3=Long|first3=D. A.|last4=Skinner|first4=M.|title=The pure rotational Raman spectrum of SeO₃|journal=Journal of Raman Spectroscopy|volume=7|issue=3|year=1978|pages=158–160|issn=0377-0486|doi=10.1002/jrs.1250070310|bibcode=1978JRSp....7..158B}}</ref>

==References==

{{reflist}}

==Further reading==

*{{Greenwood&Earnshaw}}

*{{cite journal |last1=Schmidt |first1=Prof. Dr. Max |last2=Bornmann |first2=Dr. P. |last3=Wilhelm |first3=Dr. Irmgard |date=1963-10-02 |title=The Chemistry of Selenium Trioxide |journal=Angewandte Chemie International Edition in English |volume=2 |issue=11 |pages=691–692 |doi=10.1002/anie.196306913}}

{{Selenium compounds}}

{{Oxides}}

{{DEFAULTSORT:Selenium Trioxide}}

[[Category:Oxides]]

[[Category:Selenium(VI) compounds]]

[[Category:Oxidizing agents]]

[[Category:Interchalcogens]]