A series of tri-radicals with heterospin center of 1,3,5- trisubstituted benzee as feeomagnetic coupling unit has been studied by using quantum chemical DFT UB3LYP method. The result shows that partoccupied near-degenerate orbitals split value and diaferromagnetic coupling increases when symmetry of heterotri-radicals decreases. Ferromagnetic coupling can be obtained when the tri-radicals of two isospin and one heterospin center maintain the symmetry of C_(2v). Commonly, these molecules follow the rules that small ΔE_(POMO) and large ΔE_(D-Q) values lead to a stable quarlet ground state and the stability correlates to the 2,4,6-carbon position on benzee ring and the spin density of the radical atom.

Key words: BENZENE, FREE RADICAL, FERROMAGNETIC MATERIALS, SPIN, ORBITS, COUPLING