C8H6IN3O4: a birefringent crystal induced by uniformly aligned hybrid groups

C 8 H 6 IN 3 O 4 exhibits a substantial birefringence of 0.55 at 550 nm, surpassing commercially available birefringent materials, and this phenomenon is attributed to the uniform alignment of π-conjugated [NO 3 ] − and [C 8 H 6 IN 2 O] + groups.