Diels–Alder reaction
Whereas pyridine does not normally undergo a Diels–Alder reaction, arsabenzene behaves as a diene with hexafluoro-2-butyne. The corresponding phosphorine and benzene undergo the analogous reaction at 100 °C and 200 °C, respectively. Thus the ability of these heterobenzenes to undergo the Diels Alder reaction with this electrophile increases down the periodic table. Bismabenzene is so reactive that it exists in equilibrium with its dimer.