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Published June 10, 2009 | Supplemental Material
Journal Article Open

Explanation of the colossal detonation sensitivity of silicon pentaerythritol tetranitrate (Si-PETN) explosive


DFT calculations have identified the novel rearrangement shown here for decomposition of the Si derivative of the PETN explosive [pentaerythritol tetranitrate (PETN), C(CH_2ONO_2)_4] that explains the very dramatic increase in sensitivity observed experimentally. The critical difference is that Si-PETN allows a favorable five-coordinate transition state in which the new Si−O and C−O bonds form simultaneously, leading to a transition state barrier of 33 kcal/mol (it is 80 kcal/mol for PETN) and much lower than the normal O−NO_2 bond fission observed in other energetic materials (40 kcal/mol). In addition this new mechanism is very exothermic (45 kcal/mol) leading to a large net energy release at the very early stages of Si-PETN decomposition that facilitates a rapid temperature increase and expansion of the reaction zone.

Additional Information

© 2009 American Chemical Society. Received December 12, 2008. We thank the Army Research Office (W911NF-05-1-0345) and the Office of Naval Research (N00014- 09-1-0634) for financial support. Supporting Information: Comparison of B3LYP and M06 for various bond energies, all single-bond scans, IRC scans along with the change of important bond length, and unimolecular reaction rates for reactions 4 and 5. This material is available free of charge via the Internet at http://pubs.acs.org.

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Supplemental Material - Liu2009p4772J_Am_Chem_Soc_supp.pdf


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