Abstract
[1,2,3,4]Tetrazino‐[5,6‐e]‐[1,2,3,4]tetrazine‐[1,3,5,7]tetraoxide (TTTO, C~2~N~8~O~4~) was suggested to be a possible candidate of high energy density materials (HEDM). The most stable conformation of TTTO is a planar structure with C~2h~ symmetry. Using various high‐level ab initio methods including Gaussian‐n, Complete Basis Set, Full Coupled Cluster, and W1U models of chemistry together with density functional theory based models, the enthalpies of formation of TTTO at 0 K and standard state were calculated precisely. Moreover, the rovibrational and nuclear magnetic resonance properties were predicted as well. The solid state TTTO was studied using the crystal packing models with the Dreiding force‐filed and the plane‐wave periodic local‐density approximation density functional theory. Three stable polymorphous cells of TTTO have been found with either P212121 or P21/C symmetry. The high heat of formation (>200 kcal/mol), the high density (>2.0 g/cm^3^), the planar nonpolar electronic structure, and the perfect oxygen balance lead TTTO be a very promising HEDM with exceptional performance. This work provides the first theoretical support for further experimental synthesis and testing. © 2008 Wiley Periodicals, Inc. J Comput Chem 2009