Thorium monoxide (thorium(II) oxide), is the binaryoxide 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.[3] Thorium monoxide molecules contain a highly polarcovalent 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.[4][5][6][7]
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.[8]
At extremely high temperatures, thorium dioxide can convert to the monoxide either by a comproportionation 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]
^ abHoch, Michael; Johnston, Herrick L. (1954). "The Reaction Occurring on Thoriated Cathodes". J. Am. Chem. Soc. 76 (19): 4833–4835. doi:10.1021/ja01648a018.
^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. PMID17912418.
