thorium monoxide

{{chembox

| Name = Thorium monoxide

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| IUPACName = Thorium monoxide
Thorium(II) oxide

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|Section1={{Chembox Identifiers

| CASNo_Ref =

| CASNo = 12035-93-7

| PubChem =

| InChI = 1S/O.Th

| InChIKey = OEANRDRPVNMNRM-UHFFFAOYSA-N

| SMILES = [Th]=O

}}

|Section2={{Chembox Properties

| Formula = ThO

| MolarMass = 248.04 g·mol⁻¹

| Appearance = black solid{{cite encyclopedia |first= Wolfgang |last= Stoll |encyclopedia= Ullmann's Encyclopedia of Industrial Chemistry |publisher= Wiley-VCH |location= Weinheim |chapter= Thorium and Thorium Compounds |year= 2011 |doi= 10.1002/14356007.a27_001 |isbn= 978-3527306732 }}

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| Section3 = {{Chembox Structure

| CrystalStruct = face-centered cubic

| LattConst_a = 4.31 Å

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}}

Thorium monoxide (thorium(II) oxide), is the binary oxide of thorium having chemical formula ThO. In the vapor phase, it is a diatomic molecule.

Gaseous (molecular) form

Laser ablation of thorium in the presence of oxygen produces vapor-phase thorium monoxide.{{cite journal| title=The pure rotational spectrum of the actinide-containing compound thorium monoxide | doi = 10.1039/B709343H| date=2007| last1=Dewberry| first1=Christopher T.| last2=Etchison| first2=Kerry C.| last3=Cooke| first3=Stephen A.| journal=Physical Chemistry Chemical Physics| volume=9| issue=35| pages=4895–4897| pmid=17912418 |bibcode=2007PCCP....9.4895D}} Thorium monoxide molecules contain a highly polar covalent bond. The effective electric field between the two atoms has been calculated to be about 80 gigavolts per centimeter, one of the largest known internal effective electric fields.{{Cite journal|last=Skripnikov|first=L. V.|date=2016-12-07|title=Combined 4-component and relativistic pseudopotential study of ThO for the electron electric dipole moment search|journal=The Journal of Chemical Physics|language=en|volume=145|issue=21|pages=214301|doi=10.1063/1.4968229|pmid=28799403|issn=0021-9606|arxiv=1610.00994|bibcode=2016JChPh.145u4301S |s2cid=42337394}}{{Cite journal|last1=Denis|first1=Malika|last2=Fleig|first2=Timo|date=2016-12-07|title=In search of discrete symmetry violations beyond the standard model: Thorium monoxide reloaded|journal=The Journal of Chemical Physics|language=en|volume=145|issue=21|pages=214307|doi=10.1063/1.4968597|pmid=28799357|bibcode=2016JChPh.145u4307D |issn=0021-9606}}{{Cite journal|last1=Skripnikov|first1=L. V.|last2=Petrov|first2=A. N.|last3=Titov|first3=A. V.|date=2013-12-14|title=Communication: Theoretical study of ThO for the electron electric dipole moment search|journal=The Journal of Chemical Physics|language=en|volume=139|issue=22|pages=221103|doi=10.1063/1.4843955|pmid=24329049|issn=0021-9606|arxiv=1308.0414|bibcode=2013JChPh.139v1103S |s2cid=42153944}}{{cite web|url=http://www.electronedm.org/|title=The ACME EDM Experiment|website=electronedm.org|access-date=2018-08-16}}

Solid form

Simple combustion of thorium in air produces thorium dioxide. However, exposure of a thin film of thorium to low-pressure oxygen at medium temperature forms a rapidly growing layer of thorium monoxide under a more-stable surface coating of the dioxide.{{cite journal |first1= Heming |last1= He |first2= Jaroslaw |last2= Majewski |first3= David D. |last3= Allred |first4= Peng |last4= Wang |first5= Xiaodong |last5= Wen |first6= Kirk D. |last6= Rector |title= Formation of solid thorium monoxide at near-ambient conditions as observed by neutron reflectometry and interpreted by screened hybrid functional calculations |journal= Journal of Nuclear Materials |volume= 487 |year= 2017 |pages= 288–296 |doi= 10.1016/j.jnucmat.2016.12.046 |doi-access= free |bibcode= 2017JNuM..487..288H }}

At extremely high temperatures, thorium dioxide can convert to the monoxide either by a comproportionation reaction (equilibrium with liquid thorium metal) above {{convert|1850|K|°C °F}} or by simple dissociation (evolution of oxygen) above {{convert|2500|K|°C °F}}.{{cite journal |title= The Reaction Occurring on Thoriated Cathodes |first1= Michael |last1= Hoch |first2= Herrick L. |last2= Johnston |journal= J. Am. Chem. Soc. |year= 1954 |volume= 76 |issue= 19 |pages= 4833–4835 |doi= 10.1021/ja01648a018 }}

:{{chem2 | ThO2 + Th_{(l)} <-> 2 ThO_{(s)} }}

:{{chem2 | ThO2 -> ThO_{(s)} + ½ O2 }}

References

Category:Oxides

Category:Thorium compounds

Category:Rock salt crystal structure