Laser ablation of thorium in the presence of oxygen produces vapor-phase thorium monoxide.[3] Thorium monoxide molecules contain a highlypolarcovalent 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]
Simplecombustion of thorium in air producesthorium 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 acomproportionation 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]
^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.
