Magnetic Property of 1,3,5-Tris(4′,4′,5′,5′-tetramethylimidazolin-2′-yl)benzene 3′,3′′,3′′′-Trioxide 1′,1′′,1′′′-Trioxyl in 1 : 1 Mixed Crystals with 1,3,5-Trinitrobenzene

Temperature dependence of magnetic susceptibility of 1,3,5-tris(4′,4′,5′,5′-tetramethylimidazolin-2′-yl)benzene 3′,3′′,3′′′-trioxide 1′,1′′,1′′′-trioxyl was measured by a Faraday type magnetic balance on a neat sample and on mixed crystals with 1,3,5-trinitrobenzene (1:1). While the triradical in a powdered sample behaves like three monoradicals (3 × S = 1/2) following the Curie-Weiss law (θ = −14 K), the intramolecular ferromagnetic coupling (J/kB = 23 K) becomes detectable in the mixed crystals.