Tropylium bromide (7-bromo-1,3,5-cycloheptatriene) is insoluble in nonpolar solvents but dissolves readily in water. When an aqueous solution of tropylium bromide is treated with silver nitrate, a precipitate of AgBr forms immediately. The melting point of tropylium bromide is above 200 degree C, quite high for an organic compound. How can you account for these experimental observations?