Magnetic anisotropy parameters of matrixisolated septet 1,3,5trinitreno2,4,6trichlorobenzene

symmetry are negative and mutually enhance the magnetic anisotropy ofthese molecules. The contribution of the spinorbit coupling to the magnetic anisotropy of1,3,5trinitreno2,4,6trichlorobenzene is higher than 11% due to the presence of three chlorine atoms in the molecule. This suggests the possibility of further strengthening the magneticproperties of septet 1,3,5trinitrenobenzenes by introducing bromine and iodine atoms intopositions 2, 4, and 6 of their benzene rings.