Thorium monoxide

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Thorium monoxide
Names
IUPAC names
Thorium monoxide
Thorium(II) oxide
Identifiers
Properties
ThO
Molar mass 248.04 g·mol−1
Appearance black solid[1]
Structure
face-centered cubic
a = 4.31 Å
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Thorium monoxide (thorium(II) oxide), is the binary oxide of thorium having chemical formula ThO. The covalent bond in this diatomic molecule is highly polar. The electric field between the two atoms has been calculated to be 84 gigavolts per centimeter, one of the largest known internal electric fields.[3]

Simple combustion of thorium in air produces thorium dioxide. However, laser ablation of thorium in the presence of oxygen gives the monoxide.[4] Additionally, 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.[5]

At extremely high temperatures, thorium dioxide can convert to the monoxide either in by an disproportionation reaction (equilibrium with liquid thorium metal) above 1,850 K (1,580 °C; 2,870 °F) or by simple dissociation (evolution of oxygen) above 2,500 K (2,230 °C; 4,040 °F).[2]

References[edit]

  1. ^ Stoll, Wolfgang (2011). "Thorium and Thorium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a27_001.
  2. ^ a b Hoch, Michael; Johnston, Herrick L. (1954). "The Reaction Occurring on Thoriated Cathodes". J. Am. Chem. Soc. 76 (19): 4833–4835. doi:10.1021/ja01648a018.
  3. ^ "The ACME EDM Experiment". electronedm.org. Retrieved 2018-08-16.
  4. ^ Dewberry, Christopher T.; Etchison, Kerry C.; Cooke, Stephen A. (2007). "The pure rotational spectrum of the actinide-containing compound thorium monoxide". Physical Chemistry Chemical Physics. 9 (35): 4895–4897. Bibcode:2007PCCP....9.4895D. doi:10.1039/B709343H. PMID 17912418.
  5. ^ He, Heming; Majewski, Jaroslaw; Allred, David D.; Wang, Peng; Wen, Xiaodong; Rector, Kirk D. (2017). "Formation of solid thorium monoxide at near-ambient conditions as observed by neutron reflectometry and interpreted by screened hybrid functional calculations". Journal of Nuclear Materials. 487: 288–296. doi:10.1016/j.jnucmat.2016.12.046.